chore(dead-code): phase 2 trim pages shim cascade + packages/common monorepo

[Agions]

🐱 Dead Code Cleanup — Phase 2 (radical, ~30 files / -2,586 lines / ~190 KB)

Summary

Continues Phase 1 cleanup. Two unrelated workstreams bundled because they share the same root cause (left-over scaffolding from in-progress refactors that were never finished):

1. 🅲️ Pages shim cascade — 5 shim-to-shim re-exports deleted, 2 routers migrated to canonical paths
2. 🅳️ packages/common/ monorepo trim — 7 sub-directories with zero project references removed, package pruned to constants-only

🅲️ Pages shim cascade

The 4 capital-case pages/{AutoPipeline,ProjectEdit,ProjectEdit/ScriptDetail,ProjectDetail}/ directories were 2-line shims that re-exported the lowercase pages/{auto-pipeline,project-detail,project-edit}/ siblings. They existed only to give the router nice PascalCase import paths. Both routers (app/router/page-preload.ts + core/router/page-preload.ts) now use the lowercase canonical paths directly.

Deleted (5 files):

• src/pages/AutoPipeline/AutoPipelinePage.tsx
• src/pages/ProjectDetail/ProjectDetailPage.tsx
• src/pages/ProjectEdit/ProjectEditPage.tsx
• src/pages/ProjectEdit/ScriptDetailPage.tsx
• src/pages/index.ts (also pointed at shims)

Modified:

• src/app/router/page-preload.ts — 3 dynamic imports: @/pages/Project{Edit,Detail}/* → @/pages/project-{edit,detail}/*, @/pages/AutoPipeline/* → @/pages/auto-pipeline/*
• src/core/router/page-preload.ts — same 3 + 1 scriptDetail path

🅳️ packages/common/ monorepo trim

Original design (per docs/adr/0002-frontend-monorepo-ddd.md) was to split the project into a publishable monorepo package with utils/formatters/motion/hooks/components/domain/validation sub-paths. Zero project files actually import any of these — only constants is referenced (4 sites in MusicTab/SfxTab/audio.entities/VideoExporter). The other 7 sub-directories sat at 192 KB of dead code.

Deleted (17 files + 3 empty dirs + 1 README):

• packages/common/src/utils/ (16 KB)
• packages/common/src/formatters/ (12 KB)
• packages/common/src/motion/ (8 KB)
• packages/common/src/hooks/ (20 KB)
• packages/common/src/components/ui/{FileUploader,ProgressBar,Modal,ConfirmDialog}.{tsx,module.css} (44 KB)
• packages/common/src/domain/{character,scene,script,shared,index}.ts (44 KB)
• packages/common/src/validation/ (empty dir)
• packages/common/eslint-rules/ (empty dir)
• packages/common/tests/ (empty dir)
• packages/common/README-before-after.md (transitional DRY-illustration doc)

Modified:

• packages/common/src/index.ts — shrunk to export * from './constants' + comment explaining the trim and pointing at docs/adr/0002 for original design intent
• packages/common/package.json — removed 5 dead exports entries (./* sub-paths), kept peerDependencies and devDependencies intact for future monorepo resurrection

🐛 Two latent bugs exposed (not fixed — out of scope)

Removing the broken @/pages/ProjectEditPage skip-listing surfaced two pre-existing issues that were hidden behind testPathIgnorePatterns entries in jest.config.cjs. Both are now re-skipped with a more accurate comment so a future "form refactor" PR can pick them up:

1. ProjectEditPage.tsx useForm API mismatch — const [form] = useForm() as any (line 95) destructures the return value of useForm() as a tuple, but the actual export from @/components/ui/ui-components is useRhfForm (react-hook-form) which returns an object. Triggers TypeError: object is not iterable (cannot read property Symbol(Symbol.iterator)) at first render. A NOTE comment in the source already flags this as "intentional until form refactor".
2. __tests__/pages/project-{edit,detail}.test.tsx import paths — both used @/pages/ProjectEditPage / @/pages/ProjectDetailPage (no sub-dir, no extension) which never existed as a real module. Fixed to the canonical lowercase paths in this PR so the tests can run, then re-skipped under the new "form refactor" reason.

Files re-skipped with new reason in jest.config.cjs:

• src/__tests__/pages/project-edit.test.tsx
• src/__tests__/pages/project-detail.test.tsx

Verification

Check	Result
npm run lint --quiet	✅ 0 errors
npx tsc --noEmit	✅ 0 errors
npm test --runInBand (90 suites)	✅ 1596 pass, 4 skip, 0 fail
npm run build	✅ OK (vite build + brotli compress)

Diff

 30 files changed, 23 insertions(+), 2586 deletions(-)

Phase summary

Phase	Files deleted	Lines deleted	Volume
Phase 1 (PR #5)	26	2,774	~72 KB
Phase 2 (this PR)	30	2,586	~190 KB
Total	56	5,360	~262 KB

Lesson reinforced

1. Dynamic import('@/...') string literals are invisible to static import regex sweeps. Phase 1 missed 2 shims (components/business/CompositionStudio + RenderCenter); Phase 2 caught all 4 pages shims because the routers use the same pattern. The tsc --noEmit safety net caught the first batch immediately — always run it after every git rm cycle.
2. testPathIgnorePatterns is a smell audit point — 2 tests in there were broken since v1.x and silently skipped. Dead-code sweeps are a good time to audit ignore lists for stale entries.
3. "In-progress refactor" code is the biggest source of dead code — both phases' deletions (back-compat shims + monorepo scaffolding + page re-exports) were the residue of refactors that started but never finished. Either finish the refactor or strip the scaffolding; don't leave both.