Show full Google Drive paths in picker search results

[jlewi]

The Drive picker shows indistinguishable rows when folders share a name. Search results now show ${DRIVE} / ${PATH} / ${NAME} beneath each folder or file, with explicit partial paths when ancestors are inaccessible.

The resolver reuses search metadata and root names, coalesces shared-ancestor lookups, and limits concurrent reads to six. Results remain selectable while paths load. Navigation, new searches, credential changes, and unmount cancel enrichment and reject late callbacks. Shortcut paths follow the canonical target and preserve resource keys. The cache is search-scoped to avoid stale ancestry across searches.

Design: 20261003_google_drive_full_paths.runme

Validation:

• runme run build test passed.
• Full app suite: 178 files / 1,909 tests passed; focused picker/resolver suite passes all 34 tests on this commit.
• Changed-file ESLint and git diff --check passed.
• App typecheck has the same 125 existing diagnostics as base a6dea4e; no new diagnostics.
• Browser exercised the production dialog and resolver against a read-only Go fixture: verified three duplicate names with full/partial paths and selection of team-notebooks.
• Reviewed cancellation, cache scope, permissions, shortcut identity, and request bounds; fixed shortcut-to-unknown-Drive-root resolution and added regression coverage.

Reproducible CUJ and screenshot. No storage migration or new permissions. Multipart batching is deferred; this version uses bounded concurrent GETs and memoized ancestors.