feat: browse all sessions in the operations atlas

[jonts-ai]

Summary

Make Operations browse-first rather than requiring a tracker-bound outcome or a known search term.

• Open on All sessions from the native cached catalog; retain sessions without tracker links.
• Offer channel, agent, activity, outcome, role and topic stacks, composable drill-down breadcrumbs, search, status filters and density zoom.
• Join optional work relationships only by exact session identity. Preserve unassigned work and opt-in inference; keep the existing evidence graph available.
• Show catalog observation time and explicit loading/coverage states; render cards in batches with Show more. Bound loading to 5,000 sessions / 8 MiB.
• Keep missing token accounting unknown and fix zero-age sessions being treated as inactive.
• Load summaries on demand with timeouts and relative URLs. A summary failure leaves metadata usable.
• Preserve privacy filtering and English/Chinese localization; no extra SSE stream or tracker connection.
• Document isolated, pinned-source testing without requiring a registry release.

Validation

• 297 tests pass; lint has no errors, build, full formatting and repository checks pass.
• Browser-verified root and prefixed paths, mobile layout, English/Chinese switching, stack/filter/back/reset interactions, progressive loading, summary requests and privacy-failure clearing using synthetic data.
• Verified session browsing remains available with the optional work-graph endpoint unavailable.

Scope

Read-only manual-refresh catalog snapshot for the configured runtime, not fleet-wide discovery. Density zoom is not a free-pan graph canvas. Automatic semantic clustering, delivery forecasts and tracker synchronization are not included. No merge, deployment or registry release performed.

Co-authored-by: Jonathan Tsai jontsai@users.noreply.github.com