feat(editor): R-00364 M6-E CSV/TSV export, editor_static, CI, and docs

[Go1c]

R-00364 M6-E export, editor_static, CI, E2E, docs

export_tables writes UTF-8 BOM CSV/TSV with four-state source tokens, formula quoting, and README. Host POST /api/export / GET /api/exports/{id}/{file}. Vite build.outDir is src/lumio_config/editor_static (committed). CI jobs editor and editor-e2e. check-deps is in pnpm lint.

Acceptance

1. CSV/TSV UTF-8 BOM; =1+1 stored as '=1+1; README has GENERATED / NOT AUTHORITATIVE, revision, fingerprints, source. (Python test_editor_export + e2e host-export.)
2. serve reads editor_static/; CI pnpm build then git diff --exit-code -- src/lumio_config/editor_static.
3. Temporary @univerjs-pro/sheets in lockfile makes check-deps fail; restored. pnpm lint runs check-deps.
4. §5 matrix mapped in editor/docs/e2e-report.md; 26 Playwright tests passed; docs/reference/editor.md covers start through export and error codes.

Closeout

• unittest discover: 128 OK (1 skipped)
• validate / format --check / export / spec-lint / git diff --check: OK
• pnpm lint / test: 37
• pnpm build + pnpm e2e: 26 passed

Do not merge until evaluator-authorized dispatcher merge.