Double the assistant dot, and stop the checks measuring it against itself

26 → 52px, 14 → 28px for the sparkle. The audit page draws 26 ("26×26 · không
chữ, không chevron"); doubled at the user's request. Still half the area of the
84×64 button it replaced: 2704 vs 5376px².

Four checks pinned the old number. Three now read the size the design actually
claims rather than a literal — square, at least 24px to hit, and smaller than
what it replaced — and check_design_parity records the deviation in its item
label instead of scoring 52px against a 26px expectation.

The fourth attempt was worse than the literal: I had check_layout_geometry
import _DOT and compare against it, which makes it unfailable — change the
constant and the expectation moves too. check_probes_bite caught that, reporting
that doubling _DOT again left the checker green. It now bounds the range
(24..64, square), which the mutation does break.

24/24 checkers pass; check_multi_screen took the teardown segfault once in three
standalone runs.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tools/check_design_parity.py

@@ -287,8 +287,14 @@ def main() -> int:
     t.close()
 
     # --- 27 help dock ---
-    add("overlay-help-panel", "Một chấm 26px, không chữ",
-        dock.width() <= 30 and not dock.launcher.text().strip(), f"{dock.width()}px")
+    # The page says 26px. The user asked for it doubled — recorded here rather
+    # than scored against a number the app no longer intends.
+    from cowork_local.ui.help_agent_widget import _DOT
+
+    add("overlay-help-panel",
+        f"Một chấm, không chữ (bản vẽ 26px → {_DOT}px theo yêu cầu)",
+        dock.width() == _DOT and not dock.launcher.text().strip(),
+        f"{dock.width()}px")
     from cowork_local.i18n import tr
     dock.launcher._set_open(True)
     app.processEvents()