docs: add Phase 1B planning notes

- Stream retention GUI design
- Region picker for bbox selection
- API key management requirements

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/PHASE-1B-NOTES.md

@@ -0,0 +1,55 @@
+# Phase 1B Planning Notes
+
+Design notes for Phase 1B GUI features. These are planning items, not
+implementation specifications.
+
+## Stream Retention GUI
+
+### Per-Stream Configuration
+- Show each stream from `config.streams` table
+- Editable max_age_s with preset chips: 1d, 7d, 14d, 30d, 365d
+- Custom numeric input allowed (operator can enter 90d, etc.)
+- Changes trigger NATS stream update via supervisor hot-reload
+
+### Storage Monitor
+Per stream, display:
+- **Current bytes**: Live from `nats stream info`
+- **Projected bytes**: Calculated from current rate × max_age
+- **Days remaining**: Current_bytes / rate_per_day estimate
+- Refresh: Real-time polling, not cached
+
+### Global Server Cap
+- Show `max_file_store` value as read-only reference
+- Editing requires NATS server restart (out of scope for GUI)
+- Display per-stream ceiling (30% of server cap) as context
+
+## Region Picker
+
+### Interactive Map
+- Bbox selection via click-drag rectangle
+- Same UI component for all adapters (NWS, FIRMS, USGS)
+- Stores `{north, south, east, west}` floats
+- Preview of coverage area with state/country boundaries
+
+### Preset Regions
+- Common presets: CONUS, Pacific Northwest, Mountain West
+- Quick-select buttons alongside custom draw
+
+## API Key Management
+
+### Key Storage
+- View configured API keys (alias only, not values)
+- Add new keys with alias and value
+- Values encrypted at rest in `config.api_keys`
+- Rotation: update value, track `rotated_at`
+
+### Required Keys by Adapter
+- **FIRMS** (Phase 1a-6): `MAP_KEY` for NASA FIRMS API
+- Future adapters may require additional keys
+
+## Technical Notes
+
+- All GUI changes write to `config.*` tables
+- Supervisor receives NOTIFY and hot-reloads
+- No service restarts required for config changes
+- Stream retention changes apply within 5 seconds