CHE-1495: restyle Workbench controls without outlines

[congvc-bot-x99]

Status
Author correction published. PR non-draft. Issue in_review.
Current head: 8da1a6771355bc25b088639fa7be84020b1163de.
The prior Opus verdict is FAIL for 2668e8f064cd24d2f3be1f6732bded89de15b61b.
Fresh independent different-lab verification: Opus PASS. Fresh OCR receipt: verdict 01a120ad-ac3a-785b-a289-2122d06b7f5e.

Conditions

• Base: author/CHE-1491/b1/direction-b-tokens (feat(showcase-ui): adopt Workbench tokens and Inter (CHE-1494) #156), head 724941d66e724d9cc8731e1aef9f5e97a4b808bb. B1's review state does not block B2.
• B2 started from 2307fd819966e5cfbd28631dd4b5bd16f79f88ff. B1's later test-only corrections were incorporated through an append-only merge.
• If B1 merges, retarget B2 to main. Merge order: B1 (feat(showcase-ui): adopt Workbench tokens and Inter (CHE-1494) #156), then B2 (CHE-1495: restyle Workbench controls without outlines #160).
• Direction B approval: CHE-1456 comment 01a12012-ebda-7bae-9af8-35aa45af1859. Contract: CHE-1488 sections 1, 3 and 5.
• No merge or deployment. No device access or MacBook work. Author checks do not replace independent verification.

Change

• Fill secondary buttons and tabs. Chips and segmented controls use fills. Keep text-input and select borders. Keep search and composer borders.
• Share Setup and Workspace panel tokens. Remove the floating navigation shadow.
• At 560 px and below, show a 24 × 3 px primary underline on the active tab only. The underline adds no outline or shadow.
• Remove the empty queue's dashed outline. Add browser regressions and an empty-queue component regression. Keep keyboard focus and restyled hit boxes.
• Narrow the What's New 44-pixel claim to navigation tabs and Setup controls. Correct the requested Home indentation without changing behavior.

B6 Obligation
Populated queue cards and their Stop/Cancel controls remain outside B2.
B6 must remove queue card outlines and shadows.
B6 must give each Stop/Cancel control its own minimum 44 × 44 px box instead of the current 20 × 20 px box.
The empty-queue audit fixture does not cover populated queue controls. No pseudo-element hit-area tricks.

Evidence

• Local pretest: PASS, 25 Node tests plus UI-string and theme lints. TypeScript spec compilation: PASS.
• X99 development and production builds: PASS.
• Control audit: PASS at 1440 px and 390 px, including the active-only mobile underline. The existing border and shadow checks remain green. The existing 44 px and focus checks remain green.
• Layout contract and What's New entry checks: PASS. Karma locally: NOT-RUN. Both GitHub frontend test/build jobs: SUCCESS.
• CI snapshot at 19:31 ICT on October 9, 2026: 5 checks SUCCESS, 2 Python jobs IN_PROGRESS.

The regression-only working tree on the prior head failed before the CSS fixes.
It reported the empty queue outline at both widths and the missing active cue on Workspace and Runs at 390 px.
Eight current-head PNGs accompany the CHE-1495 correction receipt, including the visible active tab at 390 px.
GitHub stack google#161 metadata records B2 at position 2 of 2. GitHub stack UI rendering is NOT-RUN.

Refs CHE-1491. This PR resolves only the B2 slice, CHE-1495.
Closes CHE-1495