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>

ui/help_agent_widget.py

@@ -36,8 +36,11 @@ _MARGIN = 18                       # gap from the window's bottom-right corner
 # bottom-right of every screen — on Cowork, right on top of the Send button —
 # for something opened a few times a day. The name now appears on hover only,
 # and "hide to the edge" moved into the panel's ⋯ menu.
-_DOT = 26                          # closed launcher (a round chip)
-_DOT_ICON = 14                     # the sparkle inside it
+# The audit page draws this at 26px ("26×26 · không chữ, không chevron").
+# Doubled at the user's request: 26 read as too small to notice on a 1920
+# screen. Still half the area of the 84×64 button it replaced.
+_DOT = 52                          # closed launcher (a round chip)
+_DOT_ICON = 28                     # the sparkle inside it
 _PILL_PAD = 12                     # extra width for the label when hovered
 _TAB_W, _TAB_H = 28, 48            # the "show" tab when hidden at the edge (was 16 wide)
 _PANEL_W, _PANEL_H = 340, 460      # expanded chat panel size