Update documentation and API tests: Bookmann → Bookhoard

Documentation updates:
- All docs/ files: Update project references
- Bruno API collection: Update collection name and tests
- Device setup guides: Update all examples
- Implementation plan: Update database schema examples
- README files: Update project references

Part of project rename to Bookhoard.

docs/SYNC_USER_GUIDE.md

@@ -94,7 +94,7 @@
    - Device will receive authentication token
 
 4. **Configure Sync**:
-   - Enter the sync URL provided (e.g., `https://bookmann.example.com/api/sync/koreader`)
+   - Enter the sync URL provided (e.g., `https://bookhoard.example.com/api/sync/koreader`)
    - Enable auto-sync
    - Set sync frequency (recommended: Every page turn)
 
@@ -103,12 +103,12 @@
 1. **From Your Device**:
    - Navigate to sync settings
    - Select "Bookhoard Sync"
-   - Enter server URL: `https://bookmann.example.com`
+   - Enter server URL: `https://bookhoard.example.com`
    - Click "Register Device"
    - Device will display registration code
 
 2. **In Your Browser**:
-   - Go to `https://bookmann.example.com/devices/approve`
+   - Go to `https://bookhoard.example.com/devices/approve`
    - Enter registration code
    - Approve the device
 
@@ -505,13 +505,13 @@ A: Yes, HTTPS/TLS 1.3 for all sync traffic.
 
 - **Issues**: Report bugs at GitHub Issues
 - **Discussions**: Join GitHub Discussions
-- **Email**: support@bookmann.example.com
+- **Email**: support@bookhoard.example.com
 
 ### Community
 
-- **Forum**: community.bookmann.example.com
-- **Matrix**: #bookmann:matrix.org
-- **Discord**: discord.gg/bookmann
+- **Forum**: community.bookhoard.example.com
+- **Matrix**: #bookhoard:matrix.org
+- **Discord**: discord.gg/bookhoard
 
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