fix(slicer): wrong-printer slicing + sliced-archive filament list + per-instance MakerWorld compat

Five stacked slice-pipeline bugs that each made the modal's profile picker
  theatrical for 3MF inputs:

  (1) `_strip_3mf_embedded_settings` removed `model_settings.config` /
      `slice_info.config` / `cut_information.xml` along with
      `project_settings.config`. The CLI silently exited after
      "Initializing StaticPrintConfigs" — exit 0, no result.json — and
      Bambuddy masked the failure by re-running with embedded settings
      and the source's bound printer. Strip removed from the dispatch
      path entirely.

  (2) Standard-tier preset stubs lacked the `type` field, so the CLI
      rejected `--load-settings` with rc=-5 ("input preset file is
      invalid") and the same masking fallback fired. Added
      `_SLOT_TO_PROFILE_TYPE` so each stub carries the right
      machine/process/filament discriminator.

  (3) Sliced-archive cards listed every project-wide AMS slot (16+
      swatches for a 2-color print). `slice_and_persist_as_archive` now
      reads `filament_type` / `filament_color` from the sliced output's
      `slice_info.config` (which `ThreeMFParser` already gates on
      `used_g > 0`) instead of inheriting from the source archive.

  (4) SliceModal had no warning when the picked printer profile didn't
      match the source 3MF — the CLI rejects cross-printer slices
      (rc=-16) and fell back to embedded settings, producing wrong-printer
      g-code that errored at print dispatch. Plates response now exposes
      `source_printer_model`; the modal compares against the picked
      profile name and disables Slice + shows an inline warning on
      mismatch.

  (5) MakerWorld URL-paste resolver listed plate instances without
      showing which printer each was sliced for (`/instances/hits`
      omits compatibility info that lives on `design.instances[]
      .extention.modelInfo`). The resolve route now joins both payloads
      by instance ID and forwards `compatibility` + `otherCompatibility`
      onto each hit; the MakerWorld page renders "Sliced for {primary}"
      + "Also marked compatible: ..." per row.

  Tests: 6 unit tests for `extract_source_printer_model_from_3mf`, 1 for
  filtered filament metadata via ThreeMFParser, 2 for makerworld resolve
  compat-merge (happy path + missing modelInfo), 3 frontend SliceModal
  tests for the printer-mismatch warning + Slice-disabled gate. New i18n
  keys `slice.printerMismatch`, `makerworld.slicedFor`,
  `makerworld.alsoCompatible` across all 8 locales.

backend/tests/integration/test_library_slice_api.py

@@ -389,9 +389,17 @@ class TestSliceLibraryFile:
 
     @pytest.mark.asyncio
     @pytest.mark.integration
-    async def test_3mf_input_strips_embedded_settings_before_forwarding(
+    async def test_3mf_input_forwarded_unmodified_to_sidecar(
         self, async_client: AsyncClient, db_session, slice_test_setup
     ):
+        # 3MF input must be forwarded to the sidecar verbatim — every
+        # Metadata/*.config the source carries (project_settings,
+        # model_settings, slice_info, cut_information) is needed by the
+        # CLI to find plate definitions and baseline config; an earlier
+        # version of this code stripped them and caused the CLI to
+        # silently exit immediately after "Initializing StaticPrintConfigs"
+        # for every 3MF slice. --load-settings overrides the specific
+        # fields the user changed; the rest comes from the embedded data.
         src_3mf_path = slice_test_setup["tmp_path"] / "library" / "files" / "real.3mf"
         src_3mf_path.write_bytes(_make_3mf_with_settings({"prime_tower_brim_width": "-1"}))
         threemf = LibraryFile(
@@ -431,20 +439,18 @@ class TestSliceLibraryFile:
         final = await _wait_for_job(async_client, response.json()["job_id"])
         assert final["status"] == "completed", final
 
-        # Recover the embedded zip from the multipart body — the strip
-        # must remove every config that references the original slice's
-        # printer / filament IDs (otherwise the CLI's input validation
-        # rejects the new --load-settings triplet, the slice fails, and
-        # we drop into the embedded-settings fallback).  Geometry stays.
+        # Recover the embedded zip from the multipart body and assert ALL
+        # the source's Metadata/*.config files are still present — the
+        # opposite of the previous (broken) "strip everything" test.
         body = captured["body"]
         pk = body.find(b"PK\x03\x04")
         assert pk >= 0, "3MF body not found in multipart payload"
         with zipfile.ZipFile(io.BytesIO(body[pk:]), "r") as zin:
             names = set(zin.namelist())
-        assert "Metadata/project_settings.config" not in names
-        assert "Metadata/model_settings.config" not in names
-        assert "Metadata/slice_info.config" not in names
-        assert "Metadata/cut_information.xml" not in names
+        assert "Metadata/project_settings.config" in names
+        assert "Metadata/model_settings.config" in names
+        assert "Metadata/slice_info.config" in names
+        assert "Metadata/cut_information.xml" in names
         assert "3D/3dmodel.model" in names
 
 

backend/tests/unit/services/test_archive_copy.py

@@ -113,6 +113,51 @@ class TestThreeMFParserErrorVisibility:
         # No assertions about which keys are present — just that it didn't blow up.
         assert isinstance(result, dict)
 
+    def test_filament_metadata_only_includes_filaments_with_used_g(
+        self,
+        tmp_path: Path,
+    ) -> None:
+        """slice_and_persist_as_archive uses parsed_metadata.filament_type/color
+        to populate the new archive's filament list. The parser must filter
+        out filaments whose used_g==0 — otherwise the resulting archive card
+        shows every project-wide AMS slot (16+ swatches) for what was
+        actually a 2-color print on a single plate.
+        """
+        p = tmp_path / "two-of-eighteen.3mf"
+        with zipfile.ZipFile(p, "w") as zf:
+            zf.writestr("3D/3dmodel.model", "<model/>")
+            # 4 declared slots, only 2 actually consumed on this plate.
+            zf.writestr(
+                "Metadata/slice_info.config",
+                """<?xml version="1.0"?>
+                <config>
+                  <plate>
+                    <metadata key="index" value="1"/>
+                    <filament id="1" type="PLA"  color="#FFFFFF" used_g="25.0" used_m="8.5"/>
+                    <filament id="2" type="PETG" color="#FF0000" used_g="0"    used_m="0"/>
+                    <filament id="3" type="PLA"  color="#000000" used_g="12.5" used_m="4.2"/>
+                    <filament id="4" type="ABS"  color="#00FF00" used_g="0"    used_m="0"/>
+                  </plate>
+                </config>""",
+            )
+
+        result = ThreeMFParser(p).parse()
+
+        # Both fields should be comma-joined strings of only the consumed
+        # filaments — slot 2 (PETG #FF0000) and slot 4 (ABS #00FF00) must
+        # not appear on the new archive card. The parser dedupes types,
+        # so both PLA slots collapse into a single "PLA" entry; colors
+        # are unique per swatch and stay distinct.
+        types = result.get("filament_type", "")
+        assert "PLA" in types
+        assert "PETG" not in types  # used_g=0 → excluded
+        assert "ABS" not in types
+        colors = result.get("filament_color", "")
+        assert "#FFFFFF" in colors
+        assert "#000000" in colors
+        assert "#FF0000" not in colors
+        assert "#00FF00" not in colors
+
 
 class TestZipFileSentinel:
     """Sanity check the sentinel the archive pipeline relies on."""

backend/tests/unit/services/test_preset_resolver.py

@@ -30,9 +30,26 @@ def test_standard_emits_inherits_stub():
         # treat this as a User-authored profile and reject it against
         # system filament/process pairs.
         "from": "system",
+        # `type` is required by the CLI's --load-settings parser. Without
+        # it the CLI silently exits with rc=-5 ("input preset file is
+        # invalid"), causing every 3MF slice to fall back to embedded
+        # settings. See preset_resolver._SLOT_TO_PROFILE_TYPE.
+        "type": "machine",
     }
 
 
+def test_standard_emits_correct_type_per_slot():
+    """Each slot maps to the right `type` value the CLI parser expects:
+    printer → machine, process → process, filament → filament. Missing or
+    wrong type causes the CLI to silently exit with rc=-5."""
+    for slot, expected_type in (("printer", "machine"), ("process", "process"), ("filament", "filament")):
+        out = preset_resolver._resolve_standard(
+            PresetRef(source="standard", id="anything"),
+            slot=slot,
+        )
+        assert json.loads(out)["type"] == expected_type, slot
+
+
 def test_standard_rejects_unknown_slot():
     with pytest.raises(HTTPException) as exc:
         preset_resolver._resolve_standard(PresetRef(source="standard", id="anything"), slot="bogus")

backend/tests/unit/test_makerworld_routes.py

@@ -136,6 +136,92 @@ class TestResolve:
         assert resp.status_code == 200, resp.text
         assert resp.json()["already_imported_library_ids"] == [existing.id]
 
+    @pytest.mark.asyncio
+    async def test_merges_compatibility_from_design_into_instances(self, async_client):
+        """Per-instance printer compatibility info lives on
+        ``design.instances[].extention.modelInfo`` but not on
+        ``/instances/hits``. Resolve enriches each hit with both
+        ``compatibility`` (primary printer the instance was sliced for) and
+        ``otherCompatibility`` (extra printers the uploader marked it
+        compatible with) so the frontend can show "sliced for A1 / also
+        marked compatible with: H2D, P1S".
+        """
+        design_payload = {
+            "id": 1400373,
+            "title": "Seed Starter",
+            "instances": [
+                {
+                    "id": 1452154,
+                    "extention": {
+                        "modelInfo": {
+                            "compatibility": ["A1"],
+                            "otherCompatibility": ["H2D", "P1S"],
+                        }
+                    },
+                },
+                {
+                    "id": 1452158,
+                    "extention": {
+                        "modelInfo": {
+                            "compatibility": ["X1 Carbon"],
+                            "otherCompatibility": [],
+                        }
+                    },
+                },
+            ],
+        }
+        instances_payload = {
+            "total": 2,
+            "hits": [
+                {"id": 1452154, "profileId": 298919107, "title": "9 cells"},
+                {"id": 1452158, "profileId": 298919564, "title": "12 cells"},
+            ],
+        }
+        svc = _fake_service(get_design=design_payload, get_design_instances=instances_payload)
+
+        with patch("backend.app.api.routes.makerworld._build_service", AsyncMock(return_value=svc)):
+            resp = await async_client.post(
+                "/api/v1/makerworld/resolve",
+                json={"url": "https://makerworld.com/en/models/1400373"},
+            )
+        assert resp.status_code == 200, resp.text
+        instances = resp.json()["instances"]
+        by_id = {i["id"]: i for i in instances}
+        assert by_id[1452154]["compatibility"] == ["A1"]
+        assert by_id[1452154]["otherCompatibility"] == ["H2D", "P1S"]
+        assert by_id[1452158]["compatibility"] == ["X1 Carbon"]
+        assert by_id[1452158]["otherCompatibility"] == []
+
+    @pytest.mark.asyncio
+    async def test_resolve_handles_missing_compatibility_gracefully(self, async_client):
+        """Older designs (or hits without a matching design.instances entry)
+        must not crash the resolve response — they just don't get the
+        compat fields."""
+        design_payload = {"id": 1400373, "instances": [{"id": 1452154}]}  # no extention
+        instances_payload = {
+            "total": 2,
+            "hits": [
+                {"id": 1452154, "profileId": 298919107},
+                {"id": 9999999, "profileId": 298919999},  # no design.instances match
+            ],
+        }
+        svc = _fake_service(get_design=design_payload, get_design_instances=instances_payload)
+
+        with patch("backend.app.api.routes.makerworld._build_service", AsyncMock(return_value=svc)):
+            resp = await async_client.post(
+                "/api/v1/makerworld/resolve",
+                json={"url": "https://makerworld.com/en/models/1400373"},
+            )
+        assert resp.status_code == 200, resp.text
+        instances = resp.json()["instances"]
+        # First instance: design entry exists but no extention → fields absent or None.
+        first = next(i for i in instances if i["id"] == 1452154)
+        assert first.get("compatibility") is None
+        assert first.get("otherCompatibility") is None
+        # Second instance: no design entry at all → no enrichment, no crash.
+        second = next(i for i in instances if i["id"] == 9999999)
+        assert "compatibility" not in second or second["compatibility"] is None
+
 
 class TestImport:
     """End-to-end of POST /makerworld/import — mocks the service but exercises

backend/tests/unit/test_threemf_tools.py

@@ -13,6 +13,7 @@ from backend.app.utils.threemf_tools import (
     extract_filament_usage_from_3mf,
     extract_plate_extruder_set_from_3mf,
     extract_project_filaments_from_3mf,
+    extract_source_printer_model_from_3mf,
     get_cumulative_usage_at_layer,
     mm_to_grams,
     parse_gcode_layer_filament_usage,
@@ -645,3 +646,43 @@ class TestExtractPlateExtruderSetFrom3mf:
             # Top-level metadata still works; missing component model file
             # is silently skipped without crashing.
             assert extract_plate_extruder_set_from_3mf(zf, plate_id=1) == {2}
+
+
+# ---------------------------------------------------------------------------
+# Tests for extract_source_printer_model_from_3mf — feeds the SliceModal's
+# pre-slice mismatch warning. The CLI cannot re-slice a 3MF for a different
+# printer, so warning the user up-front avoids producing wrong-printer output.
+# ---------------------------------------------------------------------------
+
+
+class TestExtractSourcePrinterModelFrom3mf:
+    def test_returns_none_when_project_settings_missing(self):
+        with _make_3mf_with({"placeholder.txt": "hi"}) as zf:
+            assert extract_source_printer_model_from_3mf(zf) is None
+
+    def test_reads_printer_model_directly(self):
+        proj = {"printer_model": "Bambu Lab H2D"}
+        with _make_3mf_with({"Metadata/project_settings.config": json.dumps(proj)}) as zf:
+            assert extract_source_printer_model_from_3mf(zf) == "Bambu Lab H2D"
+
+    def test_falls_back_to_printer_settings_id_with_nozzle_strip(self):
+        # Older Bambu Studio exports stored the printer under
+        # printer_settings_id, often with a "0.4 nozzle" suffix the helper
+        # must strip to match the canonical model name.
+        proj = {"printer_settings_id": "Bambu Lab A1 0.4 nozzle"}
+        with _make_3mf_with({"Metadata/project_settings.config": json.dumps(proj)}) as zf:
+            assert extract_source_printer_model_from_3mf(zf) == "Bambu Lab A1"
+
+    def test_settings_id_without_nozzle_suffix_returned_as_is(self):
+        proj = {"printer_settings_id": "Bambu Lab P1S"}
+        with _make_3mf_with({"Metadata/project_settings.config": json.dumps(proj)}) as zf:
+            assert extract_source_printer_model_from_3mf(zf) == "Bambu Lab P1S"
+
+    def test_corrupt_json_returns_none_no_exception(self):
+        with _make_3mf_with({"Metadata/project_settings.config": b"{broken"}) as zf:
+            assert extract_source_printer_model_from_3mf(zf) is None
+
+    def test_empty_string_treated_as_missing(self):
+        proj = {"printer_model": "", "printer_settings_id": ""}
+        with _make_3mf_with({"Metadata/project_settings.config": json.dumps(proj)}) as zf:
+            assert extract_source_printer_model_from_3mf(zf) is None