phase: 145_git_source_links

**Phase 145 final verification pass — all green, no code changes needed**

- **Verified (no defects found):** resolver `origin_for_source` + `_url_basename` (scp/`.git`/trailing-slash, sanitize, ambiguity WARNING); `origin:`/`branch:` lines in all four read shapes via shared `_origin_lines`; HIGH `<tools>` origin rule (verbatim + only-byte-change pins); `DocContent.origin_url/origin_branch` (absent-never-null serializer); `renderDocument` "Original" anchor (copyable verbatim URL, `_blank`/`noopener`, branch in title); mock scripted origin-link flow (disjoint trigger — grep-verified vs all other E2E files)
- **Tests:** `uv run pytest --cov=app --cov-report=term-missing` → 3402 passed, `app/` coverage **99%** (>90% gate); `uv run pytest tests/e2e/test_git_source_links.py -v --no-cov` → **4 passed** in isolation; `uv run ruff check .` → clean; `uv run pyright` → 0 errors, 0 warnings
- **Completion criteria:** (1) git read results carry origin/branch, local byte-identical — ✅ (unit pins + E2E control); (2) HIGH `<tools>` rule pinned, LOW byte-identical — ✅; (3) modal AND /document.html show Original link, branch in label when pinned, nothing for local — ✅; (4) full suite green + coverage + E2E + lint/types — ✅; (5) no completed-phase behavior change (read header line 1, mock prefix, done frame/SourceRef untouched, LOW sha) — ✅
- **Extra regression check:** re-ran shared-mock E2E suites `test_read_line_ranges.py` (2 passed) and `test_document_viewer.py` (8 passed) — no cross-suite regressions from the `mock_llm.py` addition
- **Documentation:** README.md reviewed in full (env table ⊇ `.env.example`, pages/routes, config defaults, scripts, 17-color palette, 300 s guard, 2 s sync poll, phase-145 provenance section matches implementation) and AGENTS.md (72rem container, no-CDN test, smoke test, gitignore, gates) — **verified consistent, no changes needed**
- **Notable:** phase-116 screenshot PNG was regenerated during this phase's E2E runs (byte re-encode only, visually identical, correct no-anchor local-source meta row) — left in tree for the harness commit
- **Next pending phase:** `146_search_tool_scope` (then 147, 148, 149)

README.md

@@ -374,6 +374,21 @@ server-side tools — on **grounded** (high-relevance) turns only:
 
 (See [Answer images](#answer-images-phase-124) for the `show_image` tool.)
 
+**Git-source provenance (phase 145).** When a document comes from a git
+source, its `read` result also carries an `origin:` line (the repository's
+URL, credentials stripped) and, when the source pins one, a `branch:` line.
+The prompt teaches the model to include that original source in its answer —
+a link to the repository with the document's path named (and the pinned
+branch when one is shown) — so you can open the complete original in one
+step rather than asking again for the source. Local (non-git) sources carry
+no `origin:` line, so nothing is added and no link is invented. The same
+origin rides the document-content payload (`origin_url` + `origin_branch`
+when pinned), and the document viewer — the chat's doc modal AND the full
+`/document.html` page, one render site — shows it as an **Original**
+external link in the document's meta row (the full repository URL as the
+link text, opening in a new tab; the pinned branch rides the link's
+title). Non-git documents show nothing new.
+
 Each call is executed against Postgres only (no extra LLM round trip) and
 streamed as an SSE `tool` frame. In the chat, each call shows a transient
 **calling-tool status** alongside "thinking" (the send button keeps its