Lazy-load Category views stylesheet

[elkimek]

What

• defer css/category-views.css until Category, Compare, or Correlations is opened
• use the already-eager category runtime for single-flight loading, cascade preservation, failure containment, and cache-busted retry
• keep dashboard greeting spacing, alert cards, and date-range controls in eager dashboard ownership
• update route/static CSS fixtures for the new async presentation contract
• add browser coverage for cache/order, failure/retry, and eager shared-style ownership
• ratchet the cold-load budget and document the boundary

Why

Category and comparison presentation is not needed on a normal returning-user dashboard startup. A few rules in the former bundle were shared by dashboard widgets, so those rules were relocated unchanged before deferring the remaining route-only stylesheet.

Cold-load impact

Identical fresh mobile returning-user runs with browser cache and service workers disabled:

• requests: 436 → 435 (-1)
• compressed transfer: 1,841,186 → 1,836,218 bytes (-4,968)
• decoded resources: 5,562,340 → 5,539,354 bytes (-22,986)

Validation

• COVERAGE=1 ./run-tests.sh
  • 487 Node/Vitest tests
  • 413 Chromium tests
  • 472 responsive assertions
  • offline PWA and two-device sync coverage
  • 67.24% global function coverage (67.10% floor)
• npm run quality (11/11)
• type checks, architecture (465 modules, 0 cycles), vendor integrity, and 131 verification checks
• targeted route/dashboard/cold-load browser coverage (11/11)
• npm run performance:check (435 requests, 1,836,218 transfer bytes, 5,539,354 decoded bytes)