phase: 139_read_range_tool_lines

All verification is complete and green. Phase 139's three tasks (01–03) were already implemented in prior passes; this was the final verification pass, and every gate holds.

## Phase 139 — final verification report

**Verified in working tree (no code changes needed):**
- `readRangeSuffix` single-source-of-truth helper in `app.js` + byte-identical parity copy in `shared.js` (EN-dash ` (lines N–M)`, `(from line N)`, `(first N lines)`, `Number.isInteger(x) && x >= 1` guard mirroring the server's `_whole_line_number`)
- `appendToolLine(wrap, name, argument, offset = null, limit = null)` — `<span class="read-range">` sibling after `<code>`, only when suffix non-empty; `shared.js` `addToolLines` parity
- Live `tool` branch: guarded `ev.offset`/`ev.limit`, additive `toolAcc` records (non-range keeps pre-phase shape), status label carries the suffix (A2); restore path passes stored `t.offset`/`t.limit` through, phase-95 truncation note untouched
- E2E: `SAME_FILE_TRIGGER` mock flow (same file read twice, offsets 10/20 then 40/15) + 3-test Playwright suite

**Test / lint / coverage results:**
- `uv run pytest` (unit + integration): **3283 passed, 9 skipped, 0 failed**
- `uv run pytest --cov=app --cov-report=term-missing`: **TOTAL 99%** (>90% gate)
- `uv run pytest tests/e2e/test_read_range_tool_lines.py -v --no-cov`: **3 passed** in isolation
- `uv run ruff check .`: clean; `uv run pyright`: **0 errors, 0 warnings**

**Completion criteria:**
1. Range read renders `(lines N–M)` live; two same-file reads show DIFFERENT ranges — ✅ (E2E test 1)
2. Plain read byte-identical; phase-87/117 pins + emoji guard pass unedited — ✅ (E2E test 2 + full suite)
3. Suffix survives save → restore on chat page + shared page — ✅ (E2E test 3)
4. Full suite green, coverage >90%, E2E isolated green, ruff + pyright clean — ✅
5. Commit + phase move — left to the harness per executor rules (no `git add`/`commit` run)

**Notable:** the missing pytest summary line on one run was a transient output-buffering artifact, confirmed by re-run; DB was already up and healthy.

**Next pending phase:** `140_pictorial_pdf_pages`

tests/unit/test_read_truncation_frontend.py

@@ -163,7 +163,7 @@ def test_restore_path_renders_the_stored_marker() -> None:
     assert fn != -1
     end = js.find("function restoreConversation")
     body = js[fn:end]
-    assert "appendToolLine(wrap, t.name, arg)" in body
+    assert "appendToolLine(wrap, t.name, arg, tOffset, tLimit)" in body
     assert "t.truncated && arg" in body, (
         "only an argument-bearing (Reading) record with the flag renders"
         " the marker"
@@ -173,7 +173,7 @@ def test_restore_path_renders_the_stored_marker() -> None:
         " Number(t.chars_total) || 0)" in body
     )
     # The marker append sits INSIDE the tools loop, after the line append.
-    line_idx = body.find("appendToolLine(wrap, t.name, arg)")
+    line_idx = body.find("appendToolLine(wrap, t.name, arg, tOffset, tLimit)")
     note_idx = body.find("appendTruncatedNote(wrap, arg,")
     assert -1 < line_idx < note_idx