phase: 122_image_documents

**Phase 122 (image documents) — final verification pass: all green. No code changes were needed; defects found: none.**

**Verified (implementation already complete in working tree, reviewed end-to-end):**
- Toggle (`BOR_IMAGES`/`BOR_IMAGE_EXTENSIONS`/`BOR_IMAGE_DIR`, off by default) + `GET /api/config` `images` flag
- Ingest: bytes digest, `image_dir` persistent copy, `content = summary = vision description` (chat-model call; only text embedded), fail-soft skip + `images_failed` counter
- Serve/display: `/api/documents/{id}/image` route (404 matrix), viewer `<img>` + description, Sources 48px lazy thumbnails, chat inline source figure (alt = summary), agent `read` marker
- Prune guard: images-off syncs never prune `is_image` docs

**Test / lint / coverage (exact commands & outcomes):**
- `uv run pytest` → exit 0 (green; note: pytest 9.1.1 `-q` omits the final count line in output — exit code authoritative)
- `uv run pytest --cov=app --cov-report=term-missing` → **2715 passed, exit 0, TOTAL 99%** (>90% gate)
- `uv run ruff check . && uv run pyright` → "All checks passed!" / "0 errors, 0 warnings, 0 informations"
- `uv run pytest tests/e2e/test_image_documents.py -v --no-cov` → **4 passed, exit 0** (isolation)

**Completion criteria:** (1) images=true → described/embedded/displayed docs: ✅ (E2E + integration) · (2) images=false byte-identical + image docs survive sync: ✅ (E2E negative app + unit/integration) · (3) viewer + chat rendering with alt text; failed description skips + logs, sync completes: ✅ · (4) test/lint/coverage gates: ✅ · (5) commit + phase move: deferred to harness per this pass's rules (working tree left uncommitted).

**Notable deviation (pre-existing, documented in code):** image route uses `require_user` (phase-79 posture, same gate as the document content endpoint) rather than the phase text's "public" parenthetical — matches the endpoint it mirrors.

**Next pending phase:** `123_chat_image_questions`.

app/api/chat.py

@@ -224,6 +224,7 @@ from app.rag.retriever import (
     retrieve,
     select_related,
     select_suggested,
+    source_ref_with_image,
     weak_hit_titles,
 )
 from app.rag.scaffolding import ScaffoldingFilter  # phase 71: the streaming filter
@@ -984,14 +985,16 @@ async def chat(
                 # since phase 119). The UI renders the row as the
                 # de-emphasized related-docs row, never a citation chip;
                 # old clients ignore the field.
+                # Phase 122 (task 05): both tiers build their refs
+                # through the shared helper — a ref for an image doc
+                # carries the optional ``image_url`` (the bytes route),
+                # a text doc's stays byte-identical to pre-phase (the
+                # key is omitted, never null).
                 cited_refs: list[SourceRef] = []
                 if not plan.deflected:
-                    cited_refs = [
-                        SourceRef(source=d.source, path=d.path, title=d.title)
-                        for d in cited_docs
-                    ]
+                    cited_refs = [source_ref_with_image(d) for d in cited_docs]
                 related_refs = [
-                    SourceRef(source=d.source, path=d.path, title=d.title)
+                    source_ref_with_image(d)
                     for d in plan.related_docs
                     if (d.source, d.path) not in cited_seen
                 ]