Implementation plan for the read-only operator slice:

1. Extend the version-1 observation DTO only with backward-compatible collection frontier and recent sanitized sync-event summaries needed by the repository views; keep all reads aggregate/bounded.
2. Replace placeholder sections with real Overview, Caches, repository detail, and Diagnostics/Capabilities views while preserving the selected shell and System-default Light/Dark/System theme design.
3. Keep deep-link state in URL search parameters (view, cache, repo, tab, diagnostic filters) so reload/back/forward and copied local URLs retain context.
4. Make the five coverage lanes independent and non-color-coded, with explicit unknown/partial/current/blocked wording; never infer tail completeness from a bounded stop.
5. Add explicit loading, empty, partial/degraded, stale, recovered, and API-version-mismatch states plus accessible semantic controls/tables, visible focus, reduced motion, and responsive narrow layouts.
6. Verify component/type/unit coverage, mocked Playwright navigation/deep links/responsive/a11y semantics, real embedded browser flow, deterministic assets, Go tests/race checks, and public-path redaction.

No mutation controls, release/tag, or routine source install are part of this slice.

Implemented in !98.

Delivered:

• attention-first Overview, current readiness, active work, cache cohort summaries, and recovered state;
• cache → repository topology with opaque cache identities only;
• repository Coverage, Collections, Search status, and Activity tabs;
• five independent lanes with explicit textual states; bounded tail/max-pages evidence remains partial;
• current RAG truth alongside (not replaced by) contention, retry, and historical error context;
• bounded collection/frontier and recent sanitized sync summaries;
• read-only Jobs and Maintenance summaries plus typed Diagnostics and Capability catalog;
• URL-backed deep links and reload/back-forward continuity;
• explicit loading, empty, partial/degraded, stale, recovered, and API-version-mismatch states;
• semantic tabs/tables, visible focus, reduced motion, non-color status text, and 390px operability.

Verification includes full Go tests/race/vet/diff check, frontend type/unit/Playwright, deterministic embedded assets, visual comparison to the selected direction, and a live embedded-binary session/SSE/reload/theme/path-redaction smoke.

No mutation controls, release/tag, or routine source install were produced.