feat(teacher-dashboard): move Redux slice + Tier 3 + standalone dev host

[stephenliang]

Summary

Move the `teacherSections` Redux slice + all Tier 3 homepage components into the package via `git mv`, with import-path codemod across ~146 apps files. Includes the standalone MSW dev host with 6 personas — the demoable prototype.

Stacked on #74059 (leaf moves).

The diff

225 files changed, 2018 insertions, 1041 deletions.

Git detects the moves as renames (77%–100% similarity):

• 5 Redux slice files + 2 test files → `src/redux/`
• 29 Tier 3 homepage components → `src/home/`
• 21 homepage test files → `src/home/tests/`
• ~146 apps files: import-path codemod (1–2 lines each)

Standalone dev host (`VITE_API_MODE=msw yarn dev`)

6 personas: established, new-teacher, archived-only, coteacher-invite, many-sections, degraded. Realistic fixture data with assigned courses, varied grades/dates/student counts, proper avatars. Real English locale strings. Vite `@cdo/*` resolver plugin stubs non-moved dependencies in serve mode.

7 Playwright visual baselines (maxDiffPixels: 0, frozen clock, 21/21 stable).

Key patterns

• `@/` alias for internal imports (matches Studio convention)
• `hostSeams` for DCDO/experiments/analytics (configured by apps adapter)
• Ambient type stubs (`cdo-ambient.d.ts`) for `@cdo/*` retained in moved files
• ESLint permissive overrides for apps-era code (lint alignment is a follow-up)

Test plan

• Build green
• Typecheck green
• PW visual baselines: 7/7 at maxDiffPixels: 0 (21/21 with 3x repeat)
• Apps jest suites pass via codemod'd imports
• Drone CI

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