Implement P5.19.a §13.19 Admin UI Overview section enhancements:
- Add "Recent Canary Failures" card to Overview section
- Displays up to 5 most recent failed canaries
- Shows canary name, index, failed assertion count, and time of failure
- Shows success message when all canaries are passing
- Add "CDC Backlog" card to Overview section
- Displays pending CDC event count
- Shows warning when backlog exists
- Add fetchCanaryStatus() and fetchCDCStatus() API functions
- Add renderCanaryFailures() and renderCDCBacklog() rendering functions
- Add formatTimeAgo() helper function for relative time display
- Update refreshData() to fetch canary/CDC status on Overview section
Data sourced from GET /_miroir/canaries endpoint (per plan §13.18).
Closes: miroir-uhj.19.1
Implements the remaining 5 Admin UI sections per plan §13.19:
**Canaries Section:**
- List/create/edit/disable canary tests
- Pass-fail heatmap visualization over time
- Seed-from-traffic capture flow
- Canary details modal with recent runs
- Integration with /_miroir/canaries API endpoints
**Shadow Diff Section:**
- Live stream of shadow traffic diffs
- Aggregated statistics (total shadowed, errors, error rate)
- Auto-refresh capability (5s interval)
- Integration with /_miroir/shadow/diff and /_miroir/shadow/stats
**CDC Inspector Section:**
- Live tail of change events via Server-Sent Events
- Filter by index and operation type
- Pause/resume/clear controls
- Current sequence and event count display
- Integration with /_miroir/changes endpoint
**Metrics Section:**
- Tabbed interface (Prometheus/Grafana)
- Prometheus query interface with quick-metric buttons
- Grafana iframe embedding support
- Common metrics: requests, duration, rebalance, degraded shards, AE mismatches
**Settings Section:**
- Read Miroir configuration with restart hints
- General and advanced settings categories
- Visual indicators for restart-required settings
- YAML editor for direct configuration edits
**Design:**
- Consistent with existing Admin UI patterns
- Responsive design with mobile support
- Modal dialogs for detailed views and editing
- Loading states and error handling
- CSS styles for all new components
**Files Modified:**
- crates/miroir-proxy/admin-ui/dist/index.html (+336 lines)
- crates/miroir-proxy/admin-ui/dist/app.js (+755 lines)
- crates/miroir-proxy/admin-ui/dist/styles.css (+240 lines)
Closes: miroir-uhj.19.4
Implements plan §13.19 sections for document browsing, query debugging,
and task monitoring in the Admin Web UI.
**Documents Section:**
- Paginated document browser per index with configurable limit/offset
- Filter builder with support for equals, notEquals, gt, gte, lt, lte, in, exists operators
- CSV/NDJSON import via drag-and-drop triggering §13.9 streaming import
- Export documents to JSON
- Dynamic table rendering based on document fields
**Query Sandbox Section:**
- Filter builder for constructing complex query filters
- Sort builder for multi-field sorting with asc/desc
- Facet-request builder for faceted search
- Instant-run with per-shard latency breakdown display
- One-click §13.20 explain integration (query plan visualization)
- Side-by-side diff vs. shadow (§13.16) for comparing live vs shadow results
**Tasks Section:**
- Active and recent tasks display with filtering by status, index, and type
- Per-node breakdown showing task distribution
- Retry/cancel functionality where applicable
- Pagination for large task lists
- Detailed task view modal with error information
**UI/UX Enhancements:**
- Consistent styling with existing admin sections
- Responsive design for mobile and desktop
- Loading states and error handling
- Progress indicators for long-running operations
Closes: miroir-uhj.19.3
Implements plan §13.19 Indexes and Aliases sections for the Admin Web UI.
**Indexes section:**
- List indexes with UID, primary key, document count, settings version, and fingerprint
- Create index modal with UID and primary key fields
- Delete index with confirmation (requires retyping index name)
- Settings viewer/editor with live 2PC preview:
- Display current settings as JSON
- Edit settings in textarea
- Preview changes with diff view (added/removed/changed fields)
- Show new fingerprint before commit
- Apply changes via PATCH /indexes/{uid}/settings
**Aliases section:**
- List aliases with name, type (single/multi), current target, version, created date
- Create alias modal with type selection and target(s)
- Flip alias modal for single-target aliases (blue-green deployments)
- Delete alias with confirmation (requires retyping alias name)
- History timeline showing all alias flips with timestamps
**UI components added:**
- Modal system (overlay, content, header, body, footer)
- Form styles (inputs, labels, hints)
- Button styles (primary, secondary, danger)
- Settings editor (JSON display, textarea, diff view)
- Timeline component for alias history
- Responsive design for mobile devices
Closes: miroir-uhj.19.2
