fix(labels): replace incorrect ams_30x15 preset with correct AMS holder sizes (#1426)

Reporter — the same person who originally requested the labels
  feature in #809 — discovered that the ams_30x15 preset's 30x15 mm
  dimension didn't actually fit any variant of the MakerWorld AMS
  Filament Label Holder (model 752566) it advertised. Two new
  presets replace it:

  - ams_holder_74x33 (74 x 33 mm) matches the printable label STL
    bundled in the MakerWorld project
  - ams_holder_75x55 (75 x 55 mm) fits the cardstock-insert variant
    the reporter validated on bench

  Both cross the 20 mm height threshold so they land in the roomy
  layout branch — swatch on the left, QR on the right, multi-line
  text (brand, material, hex code, spool ID) in the middle. The
  old 30x15 mm preset couldn't fit a QR code; the new ones do.

  No DB migration: the preset name was never persisted. Callers
  scripting the old ams_30x15 value get a clean 422 at the route's
  Literal validator with the new valid values listed.

  i18n: replaced inventory.labels.templates.ams.{label,hint} with
  amsHolderSmall and amsHolderLarge across all 8 locales with real
  translations; parity guard cleaned of the stale English-fallback
  cognate entries. Parity holds at 4856 leaves per locale.

  Tests: backend label renderer + integration tests cover both new
  presets; LabelTemplatePickerModal test updated for the 6-button
  grid and the new template value in the API-call assertion.

backend/app/api/routes/labels.py

@@ -37,7 +37,8 @@ logger = logging.getLogger(__name__)
 router = APIRouter(tags=["labels"])
 
 _VALID_TEMPLATES: tuple[TemplateName, ...] = (
-    "ams_30x15",
+    "ams_holder_74x33",
+    "ams_holder_75x55",
     "box_40x30",
     "box_62x29",
     "avery_5160",
@@ -51,7 +52,14 @@ MAX_LABELS_PER_REQUEST = 500
 
 class LabelRequest(BaseModel):
     spool_ids: list[int] = Field(..., min_length=1, max_length=MAX_LABELS_PER_REQUEST)
-    template: Literal["ams_30x15", "box_40x30", "box_62x29", "avery_5160", "avery_l7160"]
+    template: Literal[
+        "ams_holder_74x33",
+        "ams_holder_75x55",
+        "box_40x30",
+        "box_62x29",
+        "avery_5160",
+        "avery_l7160",
+    ]
 
 
 def _split_extra_colors(raw: str | None) -> list[str] | None:

backend/app/services/label_renderer.py

@@ -1,9 +1,12 @@
 """PDF spool label rendering.
 
-Five fixed templates:
+Six fixed templates:
 
-- ``ams_30x15``  — 30×15 mm single label, fits the popular Makerworld AMS
-  Filament Label Holder (model 752566). One label per page.
+- ``ams_holder_74x33`` — 74×33 mm single label, matches the printable label
+  STL bundled with the Makerworld AMS Filament Label Holder (model 752566).
+  Smaller variant — the visible window in the holder. One label per page.
+- ``ams_holder_75x55`` — 75×55 mm single label, fits the cardstock-insert
+  variant of the same holder. Roomier — swatch + QR + full text column.
 - ``box_40x30``  — 40×30 mm single label, common DK/Brother roll size and a
   good fit for filament-bag/storage-bin labels (#809 follow-up). Roomy
   layout — swatch, QR, full text column with hex code.
@@ -12,6 +15,10 @@ Five fixed templates:
 - ``avery_5160`` — US Letter sheet, 25.4×66.7 mm × 30 per sheet.
 - ``avery_l7160`` — A4 sheet, 38.1×63.5 mm × 21 per sheet.
 
+The legacy ``ams_30x15`` preset (#809) was incorrect — the original 30×15 mm
+dimension didn't fit any documented variant of model 752566. Replaced by the
+two ``ams_holder_*`` presets above (#1426).
+
 The renderer is decoupled from the Spool model: callers build a ``LabelData``
 list from whatever source (local DB, Spoolman, future) so the same code path
 works in both modes.
@@ -34,7 +41,14 @@ from reportlab.lib.pagesizes import A4, letter
 from reportlab.lib.units import mm
 from reportlab.pdfgen import canvas as rl_canvas
 
-TemplateName = Literal["ams_30x15", "box_40x30", "box_62x29", "avery_5160", "avery_l7160"]
+TemplateName = Literal[
+    "ams_holder_74x33",
+    "ams_holder_75x55",
+    "box_40x30",
+    "box_62x29",
+    "avery_5160",
+    "avery_l7160",
+]
 
 
 @dataclass
@@ -180,17 +194,17 @@ def _draw_label(c: rl_canvas.Canvas, x: float, y: float, w: float, h: float, dat
 
     Two layouts, picked by available height:
 
-    - **Tight** (h < 20 mm — AMS holder): swatch on the left, three lines of
-      text on the right (brand, material+subtype, big spool ID). No QR — at
-      30×15 mm there is not enough horizontal room for swatch + text + QR
-      without truncating away the user-need fields, and the AMS holder is an
-      at-a-glance identifier where the spool ID is the killer field. The
-      box-label and Avery templates carry the QR for the other use cases.
+    - **Tight** (h < 20 mm): swatch on the left, three lines of text on the
+      right (brand, material+subtype, big spool ID). No QR — at very small
+      heights there is not enough horizontal room for swatch + text + QR
+      without truncating away the user-need fields. Kept as the safety
+      branch for any future ultra-small preset; the shipped templates all
+      land in the roomy layout below.
 
-    - **Roomy** (h >= 20 mm — box label, Avery sheets): swatch on the left,
-      QR on the right, multi-line text in the middle column. Large spool ID
-      anchored at bottom-left under the swatch so it stays readable when the
-      label is on a box on a shelf at arm's length.
+    - **Roomy** (h >= 20 mm — AMS holder, box label, Avery sheets): swatch
+      on the left, QR on the right, multi-line text in the middle column.
+      Large spool ID anchored at bottom-left under the swatch so it stays
+      readable at arm's length.
     """
     pad = 1.2 * mm
     inner_x, inner_y = x + pad, y + pad
@@ -223,7 +237,7 @@ def _draw_label_tight(
     pad: float,
     data: LabelData,
 ) -> None:
-    """AMS-holder layout (e.g. 30×15 mm). Swatch + brand/material/hex/ID, no QR."""
+    """Tight layout (h < 20 mm). Swatch + brand/material/hex/ID, no QR."""
     swatch_w = min(inner_h, inner_w * 0.35)
     swatch_y = inner_y + (inner_h - swatch_w) / 2
     _draw_swatch(c, inner_x, swatch_y, swatch_w, swatch_w, data)
@@ -365,7 +379,8 @@ def _draw_label_roomy(
 
 # (label_w_mm, label_h_mm) for single-label-per-page templates.
 _SINGLE_LABEL_SIZES_MM: dict[str, tuple[float, float]] = {
-    "ams_30x15": (30.0, 15.0),
+    "ams_holder_74x33": (74.0, 33.0),
+    "ams_holder_75x55": (75.0, 55.0),
     "box_40x30": (40.0, 30.0),
     "box_62x29": (62.0, 29.0),
 }

backend/tests/integration/test_labels.py

@@ -66,7 +66,13 @@ class TestLocalInventoryLabels:
     @pytest.mark.integration
     async def test_all_four_templates_succeed(self, async_client: AsyncClient, spool_factory):
         s = await spool_factory()
-        for template in ("ams_30x15", "box_62x29", "avery_5160", "avery_l7160"):
+        for template in (
+            "ams_holder_74x33",
+            "ams_holder_75x55",
+            "box_62x29",
+            "avery_5160",
+            "avery_l7160",
+        ):
             resp = await async_client.post(
                 "/api/v1/inventory/labels",
                 json={"spool_ids": [s.id], "template": template},
@@ -100,7 +106,7 @@ class TestLocalInventoryLabels:
         s = await spool_factory()
         resp = await async_client.post(
             "/api/v1/inventory/labels",
-            json={"spool_ids": [s.id, 99999], "template": "ams_30x15"},
+            json={"spool_ids": [s.id, 99999], "template": "ams_holder_74x33"},
         )
         assert resp.status_code == 404
         assert "99999" in resp.text

backend/tests/unit/services/test_label_renderer.py

@@ -6,7 +6,14 @@ import pytest
 
 from backend.app.services.label_renderer import LabelData, render_labels
 
-ALL_TEMPLATES = ("ams_30x15", "box_40x30", "box_62x29", "avery_5160", "avery_l7160")
+ALL_TEMPLATES = (
+    "ams_holder_74x33",
+    "ams_holder_75x55",
+    "box_40x30",
+    "box_62x29",
+    "avery_5160",
+    "avery_l7160",
+)
 
 
 def _sample(spool_id: int = 1, **overrides) -> LabelData:
@@ -58,7 +65,7 @@ def test_missing_optional_fields_does_not_crash():
             deeplink_url="https://example.test/inventory?spool=42",
         )
     ]
-    pdf = render_labels("ams_30x15", data)
+    pdf = render_labels("ams_holder_74x33", data)
     assert pdf.startswith(b"%PDF")
 
 
@@ -74,7 +81,7 @@ def test_long_strings_are_truncated_not_overflowed():
     long_brand = "A" * 200
     long_name = "B" * 300
     data = [_sample(brand=long_brand, name=long_name)]
-    pdf = render_labels("ams_30x15", data)
+    pdf = render_labels("ams_holder_74x33", data)
     assert pdf.startswith(b"%PDF")
 
 
@@ -121,9 +128,10 @@ def _render_uncompressed(template, data):
     from backend.app.services.label_renderer import _draw_label  # noqa: PLC0415
 
     # Mirror the page-size choice from render_labels but force pageCompression=0.
-    if template in ("ams_30x15", "box_40x30", "box_62x29"):
+    if template in ("ams_holder_74x33", "ams_holder_75x55", "box_40x30", "box_62x29"):
         sizes = {
-            "ams_30x15": (30.0, 15.0),
+            "ams_holder_74x33": (74.0, 33.0),
+            "ams_holder_75x55": (75.0, 55.0),
             "box_40x30": (40.0, 30.0),
             "box_62x29": (62.0, 29.0),
         }
@@ -167,9 +175,9 @@ def _render_uncompressed(template, data):
 def test_ams_template_actually_renders_text():
     """Regression: the first cut of the AMS-holder layout produced labels with
     only swatch + QR and no text at all because the side-by-side layout left
-    <5 mm for the text column. The redesign drops the QR on this template and
-    gives the right side to brand + material + spool ID. This pins that the
-    rendered PDF contains all three fields.
+    <5 mm for the text column. The current AMS templates use the roomy layout
+    (swatch + QR + multi-line text); this pins that the rendered PDF contains
+    brand + material + spool ID for the smaller AMS preset.
     """
     data = [
         LabelData(
@@ -182,7 +190,7 @@ def test_ams_template_actually_renders_text():
             deeplink_url="https://example.test/inventory?spool=42",
         )
     ]
-    pdf = _render_uncompressed("ams_30x15", data)
+    pdf = _render_uncompressed("ams_holder_74x33", data)
     assert b"Polymaker" in pdf, "AMS template must render the brand"
     assert b"PLA" in pdf, "AMS template must render the material"
     # The bracketed-hash style is what the renderer uses for the spool ID;