phase: 194_sync_pending_count

**Phase 194 — final verification pass: all green.**

**Verified (all 5 tasks already complete; nothing re-implemented needed)**
- `app/rag/importer.py`: `_prescan_pending` + `_pending_hash_stmt` (scalar `documents.file_hash`, own session, ONE `asyncio.to_thread` span, REPLACES the stats pre-walk), `on_scan_progress`, `progress` pair = pending position, `0` branch = byte-identical phase-193 walk.
- `app/config.py`/`settings_catalog.py`/`.env.example`: `sync_pending_count=1` + validator; `app/api/sync.py`: `"scan"` phase, `scan_done`/`scan_total` (additive after `files_total`, kept at every terminal), forced/throttled RSS split; `frontend/assets/sources.js`: `fmtSyncPhaseLabel` scan branch first-arm, `fmtSyncLabel` untouched.

**Tests / lint / coverage (exact commands)**
- `uv run pytest --cov=app --cov-report=term-missing` → **4835 passed**, `app/` 99% (7240 stmts / 16 miss), exit 0
- `uv run pytest tests/e2e/test_sync_pending_count.py -v --no-cov` → **8 passed in 150.81s** (phase suite, isolated)
- 14 sync-lineage E2E suites, one pytest process each (`test_sync_remaining_count`, `…_chunk_progress`, `…_progress_box`, `…_peak_memory_visible`, `…_label_mobile`, `…_upload_progress`, `test_archive_upload_sources`, `…_image_progress`, `…_summary_visibility`, `…_status_freshness`, `test_smoke`, `test_fast_path_deferred_content`, `test_sync_session_reset`, `test_sync_git_freeze`) → **all exit 0**
- `uv run ruff check .` → All checks passed; `uv run pyright` → **0 errors**

**Completion criteria** — all met: `N remaining` = predicted change set (E2E arms 1/2/5, first import counts the walk, no-change → no count part); `scan` phase visible + flips to `import`, scan pair reset/kept at terminals (`test_sync_scan_phase.py`); `BOR_SYNC_PENDING_COUNT=0` walk semantics ("7 remaining" arm) + **negative refuses startup naming the field (verified live by importing `app.main`)**; pre-scan off-loop + cancel lands `cancelled` (integration pins); CLI/upload byte-identical (unedited pins green); payload additive (`_PRE_187_STATUS_KEYS | _MEMORY_KEYS | _SCAN_KEYS`); suite green, coverage >90%, lint/types clean.

**Documentation** — 3 fixes: README sync "States" bullet had an **unclosed parenthesis** (pre-existing, 193/194) and the scan-label "total is 0" clause was ambiguous about a `=0` run (it still counts the walk once the import starts); **AGENTS.md rule 17 had a stray `)`** (pre-existing from phase 191). Also verified consistency both directions for all 87 settings ↔ README ↔ `.env.example` ↔ settings catalog, the pages table ↔ `app/main.py` routes, no stale `BOR_` names, and README/AGENTS claims through phase 194.

**Notes/deviations** — no live-infra changes (prod sync knob ships default-on, no deployment touched); no git index/history commands run (all changes left in the working tree for the harness); commit criterion left to the harness as instructed.

**Next pending phase:** none — `.agents/phases/todo/` holds only `194_sync_pending_count`, which is now ready to move to `complete/`.

tests/integration/test_import_session_retention.py

@@ -135,6 +135,18 @@ lazy SELECT per row and fail that test, not get papered over.
 **What this file does NOT touch:** the walk's column set (phase 185),
 ``scripts/git_sync.py`` (phase 186), ``app/db.py:30``, and the
 ``doc.chunks = [...]`` re-embed path (phase 183 LOCKED A2).
+
+**Why phase 194 left the bound UNCHANGED (the D5 sweep).** Several tests
+here call ``import_sources`` WITH a ``progress`` hook — so the phase-194
+pre-scan really runs on those walks. It cannot move a single number in
+this file: ``_prescan_pending`` reads the SCALAR projection
+``_pending_hash_stmt`` (one column, no entity), through a session of its
+OWN inside the ``to_thread`` span, so nothing lands in the RUN's
+``identity_map`` — the staircase, the sawtooth, the ``MAP_BOUND`` ceiling
+and the byte-identical ``ImportSummary`` / database comparisons are all
+exactly what phase 184 measured. The hydration pin the claim rests on
+(``len(session.identity_map) == 0`` at the first ``progress`` call) lives
+in ``tests/integration/test_sync_pending_count.py``.
 """
 
 from __future__ import annotations