fix: anchor project-relative docs destinations

[dvd233]

Summary

• Anchor relative sharing.docs.localDir values to the active scope base directory instead of the process cwd.
• Reuse the shared resolver from uninstall so cleanup targets the same directory that pull and doctor use.
• Preserve existing project ~/... and absolute-path behavior.

Fixes #635

Root cause

Project-scope initialization writes ./.teamai/docs. The old resolver returned that string unchanged, so pull/doctor/uninstall resolved it against whichever cwd invoked the command. This could create duplicate bundles in nested directories and let uninstall remove a user-owned cwd-relative directory while leaving the actual bundle behind.

Validation

• Regression red on origin/main: the new docs-destination test failed for both project- and user-relative paths because the resolver returned ./.teamai/docs unchanged.
• Focused regression + doctor + uninstall tests: 57 passed.
• npx tsc --noEmit: passed.
• npm run build: passed.
• Real CLI E2E after build: doctor --json resolved the relative path under the temporary HOME; uninstall --force removed the anchored TeamAI docs while preserving a packages/web/.teamai/docs/keep.md decoy.
• Full npm test: 3,436 passed; 73 existing Windows/path/permission/platform failures and one Vitest worker timeout remain unrelated to this change.
• git diff --check: passed.

[github-actions]

• [P1 blocking] Prevent empty destinations from resolving to the scope root — src/resources/docs.ts:19 converts localDir: "", currently valid under the z.string() schema, into HOME for user scope or projectRoot for project scope. uninstall --force then recursively removes that entire directory via remove(plan.docsDir). Reject empty/blank values and defensively refuse deleting the scope root.

The PR description includes a sufficient test plan and a concrete real-CLI E2E record.