feat(frontend): add native Qt workflows and fixtures

[beefiker]

Summary

• route the frontend skill explicitly across web, Qt Widgets, Qt Quick/QML, and mixed web/Qt stacks while excluding non-web/non-Qt visual work
• keep ordinary web work on the existing browser-only reference set and load Qt guidance only for Qt or explicitly mixed routes
• add native ownership, accessibility, responsive-layout, visual-state, and real-target QA contracts
• ship and harden the runnable Northstar Qt Quick Kanban and Signal Bench Qt Widgets acceptance fixtures
• make Qt Quick resilient at enlarged text, CJK/RTL layouts, clipped focus boundaries, moved-card focus restoration, and real accessibility announcements
• make the Widgets gallery deterministic against caller QPA/scale/DPI/style/locale settings, use real selection semantics, honor effective palette groups, and reject non-opaque output
• repair packaged plugin interface assets and keep public discovery/audit documentation aligned
• keep generated docs/superpowers/plans/ and docs/superpowers/specs/ artifacts untracked and excluded from packages
• retain the 0.9.2 version bump across package and plugin manifests

Why

The frontend skill was web-oriented and did not give Qt work enough framework-specific ownership, interaction, accessibility, or native-validation guidance. The new references and executable fixtures turn those expectations into tested, inspectable contracts without applying Qt discovery or validation to web-only requests.

The final review also exposed gaps in the first fixture pass: enlarged Qt Quick layouts could overlap, focus could be clipped or lost after a move, accessibility feedback was incomplete, and the Widgets gallery depended on caller state while custom painters ignored effective palette overrides. These paths now have native regression coverage.

Superpowers plans and specs are agent workflow artifacts rather than product documentation, so they no longer belong in the public repository inventory. Durable behavior remains documented in the skill references, example design files, and tests.

User impact

Qt requests now receive native framework routing and stronger implementation/QA gates. Web requests retain their browser-only route. Maintainers can run both example applications and their acceptance suites locally. Published packages contain a valid plugin icon and omit Superpowers planning artifacts.

Validation

• isolated Node suite: 557/557 passed
• node src/cli.js doctor --json: ok: true, zero dependencies, 494 audited files
• Claude plugin validation passed
• npm package dry-run: version 0.9.2, 492 files, packaged icon present, no build or Superpowers plan/spec artifacts
• Northstar Qt Quick: build passed, all_qmllint passed, CTest 4/4 passed
• Signal Bench Qt Widgets: CTest 3/3 passed; native macOS Qt Test 24/24 passed
• hostile gallery environment produced byte-identical eight-image output; production alpha validation passed
• GitHub Actions: Node 20/22 on Ubuntu, Windows, and macOS all passed (6/6)
• final independent branch review: Critical 0, Important 0, Minor 0
• git diff --check passed

Closes #25