phase: 99_kb_tree_table_and_back_nav

All verification is complete and green. Final report:

**Phase 99 — final verification pass (all 3 tasks already in `complete/`)**

- Verified the one-line Description clamp: `.kb-desc-cell` flex wrapper + `.kb-desc-text` ellipsis triad + `nowrap` column + in-cell Edit button + hover `title` + untouched level block (source diffs match D1; unit pins present)
- Verified the back-button breadcrumb nav: `applyTarget(target, push)` state-only `pushState`, no-duplicate gate, popstate adopt/reset, `bor:view-refresh` alignment before `loadTree()`, anonymous gate listener-free, router.js untouched (D2)
- `uv run pytest --cov=app`: **2180 passed**, coverage **99%** (>90% gate)
- `uv run ruff check .`: clean; `uv run pyright`: **0 errors, 0 warnings**
- `uv run pytest tests/e2e/test_kb_tree_nav.py -v --no-cov` (isolated, DB up): **4/4 passed** (back-walk, jump-then-back, fresh-nav/active-reclick, measured clamp incl. row-height parity ±4px, computed styles, full text in DOM/title/level block)
- Regression suites isolated: `test_kb_tree.py` 8✓, `test_ls_tree_drilldown.py` 3✓, `test_navbar_refresh.py` 7✓, plus `test_sync_summary_visibility.py` 3✓ (marker pin updated to `kb-desc-text kb-summary-pending` — the sanctioned class-pair change) and `test_edit_summaries.py` 4✓
- Criteria 1–4: **met** (each as above). Criterion 5 (atomic commit): left to the harness per executor rules — no `git add`/`commit` run; all changes left in the working tree
- No defects found in prior phases; no deviations. Stray `__pycache__/test_zz_smoke_tree_ui.*.pyc` is a leftover (no `.py` on disk) — inert, not touched
- Next pending phase: **none** — `todo/` will be empty once the harness moves this phase

tests/e2e/test_sync_summary_visibility.py

@@ -865,7 +865,9 @@ def test_missing_folder_summaries_read_as_pending_and_self_heal(
     src_row = page.locator("#folders-tbody tr")
     s_span = src_row.locator("td:nth-child(3) span")
     expect(s_span).to_have_text(PENDING_COPY)
-    expect(s_span).to_have_class("kb-summary-pending")
+    # Phase 99 (task 01): the marker toggles onto the cell's base
+    # .kb-desc-text span (the one-line clamp) — the class pair, exact.
+    expect(s_span).to_have_class("kb-desc-text kb-summary-pending")
     expect(s_span).to_have_attribute("title", PENDING_TITLE)
     # The Edit button is KEPT with the marker (a manual save creates
     # the row and clears the marker in place).
@@ -888,10 +890,11 @@ def test_missing_folder_summaries_read_as_pending_and_self_heal(
     expect(alpha_row.locator("td:nth-child(3) span")).not_to_have_class(
         "kb-summary-pending"
     )
-    # The affected folder: the marker (copy + class + title).
+    # The affected folder: the marker (copy + class + title) — the
+    # class pair with the phase-99 .kb-desc-text base span, exact.
     b_span = bravo_row.locator("td:nth-child(3) span")
     expect(b_span).to_have_text(PENDING_COPY)
-    expect(b_span).to_have_class("kb-summary-pending")
+    expect(b_span).to_have_class("kb-desc-text kb-summary-pending")
     expect(b_span).to_have_attribute("title", PENDING_TITLE)
 
     # Drill into the affected folder: ITS level block shows the D4