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
f83e891214