[wesbillman]

Phase 1 of slimming the test suite. Tests are 333k lines against 248k of production code, and Playwright takes 81% of CI runner time. This PR removes tests that only freeze presentation or implementation detail:

• paint values: radius, RGB, margins, fonts
• class, data-attribute and SVG-path shape
• render or call counts on mocks
• harness self-checks
• documentation inventories

No production code changes. Net −4,199 lines across 51 files.

How cuts were chosen

Candidates came from a read-only audit. Before each delete:

• A "covered by X" claim was checked against X.
• If the claim did not hold, or the test guarded real behavior, it was kept. That covers caret, persistence, revocation, origin, screen-reader semantics, Save-Data and worker cleanup.

About a third of the candidates were kept this way, for example:

• agents/tabs
• AgentAvatar
• prepared.test.ts:315 (revocation)
• view-key
• composer format/IME guards
• DeliveryNotice
• MessageTimestamp
• encode-webp

Agent review then found five deleted cases that were the only falsifier for real behavior. The second commit restores them in compact form:

Restored	Owner	Fail-then-pass
A lifetime save retired by visit or unmount while signing is held never publishes; a parent-linked session stays ineligible	sessions/SessionLifetime.test.tsx, trimmed to these cases with the real details owner	Dropping the save's abort signal fails both retirement rows
Oversized originals are never explicitly decoded	relay/media.test.ts, a two-row table	Raising the 8 MiB budget to Infinity fails the oversized row
Adding a custom emoji rebuilds the own set from a fresh read and fails closed on read failure	relay/emoji.test.ts, restored unchanged	Existing tests
Account avatar and Availability keep 4.5:1 contrast through hover and press in both themes	tests/browser/profile-contrast.spec.mjs, the contrast half of profile-avatar-gap	Passes on Chromium and WebKit
Thinking badge reverses mid-morph and settles immediately under reduced motion	viewer.spec.ts	Not run; see below

Browser cases removed

Each row gives the browser-only justification it had and what now covers it:

Removed	What covers it now
channel-activity-corners: popup inset radii	Opening an unread thread from Activity: thread-unread.spec "thread buttons show observed unread…"
scrollbar-polish: scrollbar colour, width and gutter	Settings wheel-scroll reachability: layout.spec:925–970
app-style-order: hover colour after token injection	Search open, Escape and focus return: global-search.spec "search arrows traverse…"
profile-avatar-gap: cutout paint and theme highlights	Menu keys and dismissal: settings.spec "avatar Settings access…" and account-profile.spec. Contrast is kept in profile-contrast.spec
Paint asserts in quote-styling, message-content-polish, message-delivery-polish, profiles-appearance	The same specs keep focus, keyboard, Retry, overflow, forced-colours and contrast behavior
Visual matrices in viewer.spec.ts: typography ramp, status cutout, button size, offsets, motion paint	The viewer keeps its keyboard, focus, form-reset, overflow and reduced-motion journeys

Coverage given up on purpose

• In a short viewport, the last row of the activity popover is reachable by scrolling.
• Unit coverage of useMediaCorners path generation, which is visual only.
• Native Arrow-key traversal through status Duration → Custom → expiry. StatusEditor.test.tsx still covers selection and validation.
• Jump-to-latest focus surviving an activity-lane flip.

Validation (head cb32e0b65)

Rebased onto main after #1218 and #1262. #1218 reworked three of the MessageRow tests this PR deleted: own-row alignment, attachment placement, and thread-root styling. This PR keeps #1218's new versions and leaves them for the phase 3 merges. It also keeps the new delivery-polish settle before scrolling.

• Typecheck: bin/pnpm typecheck and bin/pnpm design:typecheck are clean.
• Lint: biome is clean on the changed files.
• Unit tests: the pre-push full Vitest run passed 9,802. The only failure was a 5s timeout in the untouched InboxPage.test.tsx, which passed in isolation.
• Browser:
  • The trimmed browser specs passed on Chromium (19 tests).
  • profile-contrast.spec and the merged message-delivery-polish.spec passed on Chromium and WebKit (6 tests).
• Restored cases: mutation-checked as shown in the table above.
• Not run: tests/fixtures/design-system/viewer.spec.ts. On main it fails to load before any test runs, at src/shared/design-system/icons/claude.png: Unexpected character. It only runs from just scan, not from CI. That is pre-existing and left for a separate fix.

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