phase: 181_svg_document_preview

**Phase 181 — final verification pass (all tasks already complete; verified + docs pass)**

- Verified: `app/rag/svg_text.py` (100 % cov), vector branch in `_index_image_file`, `_row_kind_mismatch` text→image migration, `IMAGE_MIMES[".svg"]`, sandboxed CSP on `GET /api/documents/{id}/image`, `.doc-image-img--vector` in `document.js`/`styles.css`, figure/thumbnail deliberate non-changes.
- Tests/lint (exact commands): `uv run pytest --cov=app --cov-report=term-missing` → **4265 passed, TOTAL 99 %** (exit 0) · `uv run pytest tests/e2e/test_svg_document_preview.py -v --no-cov` → **5 passed in isolation** · `uv run ruff check .` → clean · `uv run pyright` → **0 errors**.
- Regression (each run in isolation, `--no-cov`, all rc=0): `test_image_documents`, `test_chat_image_questions`, `test_answer_images`, `test_chat_answer_clusters`, `test_image_anchor_context`, `test_image_upload_feedback`, `test_markdown_inline_links_images`, `test_prose_word_wrap`, `test_pdf_support`, `test_pictorial_pdf`, `test_garbage_pdf`, `test_pdf_image_extraction`, `test_pdf_image_context`, `test_pdf_pages_in_sources`, `test_pdf_strip_additive_selfheal`, `test_sync_image_progress`.
- Completion criteria: ①SVG→`is_image`+`image_path`, no vision call, own `<title>/<desc>/<text>` — **met**; ②`image/svg+xml` + `default-src 'none'; sandbox` + `private, max-age=3600`, raster headers byte-unchanged — **met**; ③chat figure → modal `<img>`, no XML — **met**; ④`/document.html` full-width vector in `.doc-image` + text below — **met**; ⑤`![alt](/api/documents/<id>/image)` paints — **met**; ⑥raster/PDF unchanged — **met**; ⑦all gates green — **met**; ⑧commit + phase-dir move — harness-owned.
- Documentation: found and fixed README inconsistencies — stale forward reference "left to phase 181 / is phase 181's job" → completed-tense sizing note; "Updating the documents" standalone-image list missing `svg`; new **Raster only** bullet for question uploads (`.svg` → 422) documenting the `chat_images` guard; missing `svg_indexed=N` / `import: svg indexed` log contract; env-table heading `122/123/124` → `122/123/124/181`; new troubleshooting entry for an `.svg` showing raw XML. Full audit: every `Settings` field and every `.env.example` var is documented; pages/commands/scripts all exist. AGENTS.md verified accurate (phase-181 §5 clause present) — no changes needed beyond what the phase wrote.
- Notable deviation (kept from task 02): `app/api/chat_images.py` subtracts `_VECTOR_IMAGE_EXTENSIONS` from the question-image accept set — a required consequence of LOCKED A7 (`svg` in the default image set) since `_CHAT_IMAGE_FILENAME_RE` refuses to *serve* `.svg`; the regex itself is untouched, as the phase specified.
- Note for the commit: changes include `README.md`, `AGENTS.md` and `.env.example` — the phase file's `git add app/ frontend/ tests/ .env.example .agents/phases/` line omits the two markdown files; stage them too.
- Next pending phase: `182_verbatim_show_text`.

app/api/chat_images.py

@@ -22,7 +22,9 @@ unguessable ``uuid4().hex`` — no enumeration value).
 The extension is the source of truth (the Content-Type header is a
 hint — the archive-uploader precedent): it must be in the phase-122
 image set (``settings.image_extension_set`` — the same frozenset the
-image-document walk uses), lowercased; total bytes are streamed with a
+image-document walk uses) minus the vector members
+(:data:`_VECTOR_IMAGE_EXTENSIONS` — a question image is RASTER-only,
+phase 181), lowercased; total bytes are streamed with a
 ``chat_image_max_mb`` cap (413, fixed detail naming the cap — never
 echoing the filename).
 """
@@ -55,6 +57,20 @@ _STREAM_CHUNK = 1 << 20
 #: upload endpoint's own naming).
 _CHAT_IMAGE_FILENAME_RE = re.compile(r"^[0-9a-fA-F]{32}\.(png|jpe?g|webp|gif|bmp)$")
 
+#: The VECTOR members of ``settings.image_extension_set`` — excluded
+#: from the question-image accept set (phase 181: the vector family
+#: belongs to INDEXING, not to question attachments). Two reasons, both
+#: hard: an OpenAI-compatible vision endpoint rejects
+#: ``image/svg+xml`` (the phase-181 LOCKED A1 reason — the vector file
+#: never reaches the describer at all), and
+#: :data:`_CHAT_IMAGE_FILENAME_RE` above deliberately refuses to SERVE a
+#: ``.svg``, so an accepted upload would be stored, unanswerable and
+#: unservable (a broken figure in the user's own bubble). Subtracting
+#: instead of touching the serve regex keeps question attachments
+#: raster-only by design while ``svg`` rides the image set for the
+#: document walk.
+_VECTOR_IMAGE_EXTENSIONS: frozenset[str] = frozenset({".svg"})
+
 
 @router.post("/chat-images")
 async def upload_chat_image(
@@ -66,10 +82,12 @@ async def upload_chat_image(
     Gates, in order:
 
     1. **extension** — the file name's extension (lowercased) must be in
-       the phase-122 image set (``settings.image_extension_set``); the
-       Content-Type header is a hint, never a source of truth (the
-       archive-uploader precedent). A missing/unknown extension is a
-       422 naming the accepted set — a fixed detail, no filename echo.
+       the phase-122 image set (``settings.image_extension_set``)
+       MINUS the vector members (:data:`_VECTOR_IMAGE_EXTENSIONS` —
+       question images are RASTER-only, phase 181); the Content-Type
+       header is a hint, never a source of truth (the archive-uploader
+       precedent). A missing/unknown/vector extension is a 422 naming
+       the accepted set — a fixed detail, no filename echo.
     2. **size** — the bytes are streamed (1 MiB chunks) with the
        ``chat_image_max_mb`` cap; over-cap is a 413 naming the cap
        (fixed detail — never echoing the filename), the temp file is
@@ -85,8 +103,9 @@ async def upload_chat_image(
     settings = get_settings()
     filename = file.filename or ""
     ext = Path(filename).suffix.lower()
-    if ext not in settings.image_extension_set:
-        accepted = ", ".join(sorted(settings.image_extension_set))
+    accepted_extensions = settings.image_extension_set - _VECTOR_IMAGE_EXTENSIONS
+    if ext not in accepted_extensions:
+        accepted = ", ".join(sorted(accepted_extensions))
         raise HTTPException(
             status_code=422, detail=f"only {accepted} images are accepted"
         )