fix: seven defects an adversarial audit found, and the gates that missed them

Every one of these was reported ok/clean to the caller while being wrong.

Silently wrong numbers
- selection_filter(min_area) read `entity.dxf.get("area", 0.0)` for SOLID,
  TRACE and HATCH, none of which carry that attribute, so every hatch
  measured 0.0. A 1600 mm^2 hatch was excluded by min_area=1.0 while
  `filtered_by` asserted the filter had run, and COM (which reads ActiveX
  .Area) returned a different selection for the same call. It now answers
  from the measurement `entity_measure` uses, so the two cannot disagree.
- Every headless dimension rendered through ezdxf's bare `Standard` style:
  1.0 mm text with a comma decimal marker, against ISO 3098's 2.5 mm minimum
  and ISO 129's point -- while the document header itself said $DIMTXT 2.5.
  `ezdxf.new(setup=True)` is not the fix; measured, it renders a 100 mm
  dimension as "10000". The attributes are now stored explicitly.
- Saving writes `dimrnd = 0.0` onto the Standard style, and ezdxf applies
  `xround(value, dimrnd)` whenever the attribute is present at all --
  `xround(33.333, 0.0)` is 33. So on any reopened file, including one this
  server saved, every dimension was rounded to a whole unit before DIMDEC
  formatted it: a 12.75 mm feature dimensioned 13. AutoCAD means DIMRND 0 as
  *no* rounding; the sentinel is now discarded at every load site, and a real
  0.5 mm rounding is left alone.
- The DIM* header fold gave out-of-range values teeth they did not have when
  they died in the header: dim_decimals=-1 returned ok and then killed the
  next dimension with `ValueError: Format specifier missing precision` from
  inside ezdxf, and 40 printed forty digits of float noise onto the sheet.
  Ranges are now AutoCAD's own (DIMDEC 0-8, DIMZIN 0-15, lengths positive).

Security
- security.py recorded the policy as "sanitize_command and sanitize_lisp each
  have exactly ONE caller ... the policy is scoped to the CHANNEL". The
  premise was false. `_ensure_linetype_loaded` and `ComBackend.linetype_load`
  build `_-LINETYPE _LOAD {name} {file}` and hand it to SendCommand, which
  treats a newline and ';' as segment separators -- so a `linetype=` argument
  carrying either injected further AutoCAD commands, and the 36-verb denylist
  never saw that channel. Guarded with the DXF symbol-name rule (the
  injection characters fall out of it rather than being enumerated) plus
  validate_path for the file argument, which was also the one path-taking
  tool reaching the filesystem unchecked. The policy comment is corrected.

Gates that could not see
- drawing_critique returned zero issues on a quarantined document: all seven
  checks wrapped their backend call in a bare `except Exception`. CLAUDE.md
  rule 7 makes that call the gate an agent is told to trust. Only the
  quarantine now escapes; an ordinary broken check still degrades.
  `_check_dimension_legibility` also read `_doc` directly from the event loop
  thread, missing the gate and performing exactly the unsynchronised access
  the quarantine exists to prevent. `construction_clear` answered
  "deleted: 0" -- there was nothing to clear -- for the same reason.
- The iso128 focus checked layer lineweights only, so a sheet lettered at
  1.0 mm critiqued clean. It now reads the effective dimension height and
  separator, header-then-style, in the order the renderer resolves.
- check_doc_numbers.py derived five values it never checked, and those were
  the ones that had drifted. The collected-test count (README said 1274, the
  tree had 1369) and the A/B pass-rate and Fixed columns are now gated.
- benchmarks/README.md's v1.4.0 table was impossible on its face -- 21
  passing plus 5 fixed is 26, not 24 -- and contradicted the report it
  linked, because `ab-v1.4.0-vs-v1.5.0.json` was regenerated from a tree that
  already carried the dimension fixes and so never measured the v1.5.0 tag.
  Replaced with a real run: ab-v1.4.0-vs-v1.5.1.json, 21/26 -> 26/26.

Release gate
- release.yml ran one ubuntu/3.11 lane, so a Windows-only defect could reach
  PyPI with no Windows job having executed. That is not hypothetical: v1.5.0
  shipped `except pywintypes.com_error` raising NameError wherever pywin32 is
  absent. It now runs the same three lanes as ci.yml, Windows included.

1368 passed, 1 xfailed. ruff clean. Tool inventory and all 16 gated document
numbers match the tree.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/test_com_timeout.py

@@ -117,6 +117,80 @@ async def test_genuine_deadline_still_rebuilds_the_executor(com_backend, monkeyp
     assert await asyncio.wait_for(com_backend._run(lambda: "fresh"), timeout=3) == "fresh"
 
 
+# ── R32 — what the timeout message must admit, and the undo mark it must record ──
+
+
+async def test_com_timeout_says_the_call_may_still_land(com_backend, monkeypatch):
+    """AutoCAD's own command processor arbitrates the abandoned call, not us.
+
+    Unlike the ezdxf backend there is no ``self._doc`` to quarantine — the
+    drawing belongs to the operator and lives in AutoCAD's process. What the
+    server *can* do is stop the message implying the operation is dead: the
+    worker is still blocked inside an uncancellable COM call, so a blind retry
+    double-applies it.
+    """
+    monkeypatch.setattr(config.settings, "com_call_timeout", 0.2)
+    release = threading.Event()
+    finished = threading.Event()
+
+    def _hang():
+        try:
+            release.wait(5.0)
+        finally:
+            finished.set()
+
+    try:
+        with pytest.raises(RuntimeError) as excinfo:
+            await com_backend._run(_hang)
+    finally:
+        release.set()
+        assert finished.wait(5)
+
+    message = str(excinfo.value).lower()
+    assert "may still" in message, "the abandoned call can still execute in AutoCAD"
+    assert "retry" in message and "double" in message
+
+
+async def test_timed_out_transaction_begin_does_not_hide_an_open_undo_mark(
+    com_backend, monkeypatch
+):
+    """RED: ``_transaction_active`` was set only after ``_run`` returned.
+
+    A timed-out ``transaction_begin`` therefore left ``StartUndoMark`` open in
+    AutoCAD while the server recorded no transaction, and the next
+    ``transaction_begin`` nested a second mark nobody could see — the exact
+    inverse of the R16 fix ``transaction_commit`` already carries.
+    """
+    monkeypatch.setattr(config.settings, "com_call_timeout", 0.2)
+    release = threading.Event()
+    finished = threading.Event()
+    marks = []
+
+    class _FakeDoc:
+        def StartUndoMark(self):
+            marks.append("start")
+            try:
+                release.wait(5.0)
+            finally:
+                finished.set()
+
+    monkeypatch.setattr(cb, "_acad_doc", lambda: _FakeDoc())
+
+    try:
+        with pytest.raises(RuntimeError, match="did not respond"):
+            await com_backend.transaction_begin()
+
+        assert com_backend._transaction_active is True, (
+            "the mark may already be set in AutoCAD; recording nothing is the unsafe direction"
+        )
+        again = await com_backend.transaction_begin()
+        assert again == {"ok": False, "error": "A transaction is already active"}
+        assert marks == ["start"], "the second begin must not nest another undo mark"
+    finally:
+        release.set()
+        assert finished.wait(5)
+
+
 def _raise_value_error():
     raise ValueError("nope")