fix(firmware): parse P2S/X2D wiki anchors without dash and full-width parens (#1030)

The wiki scraper silently returned no versions for P2S and X2D, causing
  Bambuddy to fall back to the Bambu Lab download page, which still listed
  01.01.01.00 as "latest" even though 01.02.00.00 shipped on 2026-04-09.

  Two regex mismatches in _fetch_all_versions_from_wiki():

  1. Heading anchor ids require an optional dash between version bytes and
     date. H2D/X1/H2C/H2S use "h-01020000-20260409"; P2S and X2D publish
     "h-0102000020260409" (no dash).
  2. The text fallback only matched ASCII parens around release dates, but
     P2S, X2D, A1 and A1-mini render dates in full-width parens （YYYYMMDD）
     (U+FF08/U+FF09).

  Anchor regex now accepts an optional dash; fallback accepts both paren
  styles. Added regression tests for both shapes.

backend/tests/unit/test_firmware_versions.py

@@ -50,6 +50,53 @@ async def test_wiki_extraction_returns_empty_for_unknown_api_key():
     assert await svc._fetch_all_versions_from_wiki("no-such-key") == []
 
 
+# P2S and X2D wiki pages publish anchor ids without a dash between the
+# version bytes and the date (e.g. h-0102000020260409). Regression for #1030
+# where the anchor regex required a dash and silently returned no versions,
+# causing the UI to fall back to the stale download-page "Latest" value.
+P2S_NODASH_ANCHOR_SAMPLE = """
+<h2 id="h-0102000020260409" class="toc-header">01.02.00.00（20260409）</h2>
+<h2 id="h-0101030020260209" class="toc-header">01.01.03.00（20260209）</h2>
+<h2 id="h-0101010020251208" class="toc-header">01.01.01.00（20251208）</h2>
+"""
+
+
+@pytest.mark.asyncio
+async def test_wiki_extraction_accepts_nodash_anchors():
+    """P2S/X2D anchors concatenate version+date with no dash — must still parse."""
+    svc = FirmwareCheckService()
+    mock_resp = AsyncMock()
+    mock_resp.status_code = 200
+    mock_resp.text = P2S_NODASH_ANCHOR_SAMPLE
+    with patch.object(svc._client, "get", AsyncMock(return_value=mock_resp)):
+        versions = await svc._fetch_all_versions_from_wiki("p2s")
+
+    assert [v for v, _ in versions] == ["01.02.00.00", "01.01.03.00", "01.01.01.00"]
+    assert versions[0][1] == "20260409"
+
+
+# A1, A1-mini and P2S pages render dates in full-width parens （YYYYMMDD）
+# rather than ASCII parens (YYYYMMDD). Pages without version-anchors fall
+# through to the text-based regex, so it must accept both paren styles.
+FULLWIDTH_PAREN_FALLBACK_SAMPLE = """
+<h2>01.04.00.01 （20260401）</h2>
+<h2>01.03.00.00 （20260101）</h2>
+"""
+
+
+@pytest.mark.asyncio
+async def test_wiki_extraction_fallback_accepts_fullwidth_parens():
+    svc = FirmwareCheckService()
+    mock_resp = AsyncMock()
+    mock_resp.status_code = 200
+    mock_resp.text = FULLWIDTH_PAREN_FALLBACK_SAMPLE
+    with patch.object(svc._client, "get", AsyncMock(return_value=mock_resp)):
+        versions = await svc._fetch_all_versions_from_wiki("a1")
+
+    assert [v for v, _ in versions] == ["01.04.00.01", "01.03.00.00"]
+    assert versions[0][1] == "20260401"
+
+
 @pytest.mark.asyncio
 async def test_get_available_versions_merges_sources():
     """