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-# Data Directory Structure Unification - Summary of Changes
-
-## Overview
-This change unifies the user data directory structure from a fragmented layout (with separate top-level `files/` directory) to a consistent nested format under each user's directory.
-
-## Problem Statement
-
-**Before**: Inconsistent directory structure
-- WebDAV: `data/files/<username>/`
-- CalDAV: `data/<username>/cal-<name>/`
-- CardDAV: `data/<username>/card-<name>/`
-
-**After**: Unified structure
-- All data: `data/<username>/{files,calendars,addressbooks}/<name>/`
-
-**Benefits**:
-1. All user data in a single predictable location
-2. Easier backups (single user directory instead of multiple paths)
-3. Cleaner directory structure
-4. Reduced code complexity in path resolution
-
-## Implementation Details
-
-### Files Modified
-
-1. **`internal/store/store.go`**
-   - Updated `collectionPath()` to map collection names to new unified structure:
-     - `cal-<name>` → `<username>/calendars/<name>`
-     - `card-<name>` → `<username>/addressbooks/<name>`
-     - `files` → `<username>/files`
-   - Kept `sanitize()` for security
-
-2. **`internal/store/migrate.go`** (new file)
-   - Added `Migrate()` method to restructure data directory
-   - Idempotent migration that handles both old and new structures
-   - Migrates WebDAV, CalDAV, and CardDAV data atomically
-
-3. **`internal/store/migrate_test.go`** (new file)
-   - Comprehensive tests for migration functionality
-   - Covers migration, idempotency, and edge cases
-
-4. **`internal/webdav/handler.go`**
-   - Updated WebDAV handler to use new unified path structure
-   - Changed from `dataDir/files/<username>` to `dataDir/<username>/files`
-
-5. **`internal/webdav/handler_test.go`**
-   - Updated test assertions to check new path structure
-   - Changed from `dataDir/files/alice/` to `dataDir/alice/files/`
-
-6. **`cmd/server/main.go`**
-   - Added automatic migration on server startup
-   - Ensures data directory is always in correct format
-
-7. **`tools/migrate/main.go`** (new file)
-   - Standalone migration tool
-   - Can be run independently of server
-
-8. **`tools/nidusctl/main.go`**
-   - Added `migrate` subcommand
-   - Integrated into existing admin CLI
-
-### Path Mapping
-
-| Old Path | New Path | Collection Type |
-|----------|----------|-----------------|
-| `files/<user>/<name>` | `<user>/files/<name>` | WebDAV |
-| `<user>/cal-<name>/` | `<user>/calendars/<name>/` | CalDAV |
-| `<user>/card-<name>/` | `<user>/addressbooks/<name>/` | CardDAV |
-
-## Testing
-
-All existing tests pass with the new structure:
-- ✅ Store tests (path resolution, locking)
-- ✅ CalDAV backend tests
-- ✅ CardDAV backend tests
-- ✅ WebDAV handler tests
-- ✅ Web UI tests
-- ✅ DB tests
-- ✅ Migration tests (new)
-
-Run tests:
-```bash
-go test ./... -v
-go test ./internal/store/... -run TestMigrate -v
-```
-
-## Migration Process
-
-### For Existing Installations
-
-1. **Stop the server** (optional but recommended)
-   ```bash
-   # Stop any running server
-   ```
-
-2. **Run migration**
-   ```bash
-   go run ./tools/nidusctl -config config.yaml migrate
-   ```
-
-3. **Verify migration**
-   ```bash
-   ls -la data/
-   # Should see user directories with unified structure
-   ```
-
-4. **Start the server**
-   ```bash
-   go run ./cmd/server -config config.yaml
-   ```
-
-### For New Deployments
-
-No migration needed - the new structure is used by default:
-- Server creates `<username>/files/`, `<username>/calendars/`, etc.
-- All data follows the unified structure from the start
-
-## API Compatibility
-
-**URL structure remains unchanged**:
-- CalDAV: `/cal/`, `/cal/home/<name>/`, `/cal/home/<name>/<object>`
-- CardDAV: `/card/`, `/card/home/<name>/`, `/card/home/<name>/<object>`
-- WebDAV: `/files/`
-
-Only the **on-disk path structure** changed. All HTTP endpoints and URL paths remain identical.
-
-## Security
-
-- Path sanitization maintained via `sanitize()` function
-- No security-sensitive code changed
-- Locking mechanism unchanged (still per-user)
-- All same security checks apply
-
-## Performance
-
-No measurable performance impact:
-- Same number of filesystem operations
-- Same lock granularity (per-user)
-- Same cache behavior
-
-## Rollback
-
-If rollback is needed:
-1. Restore data directory from backup
-2. Restart server (will migrate again on next startup)
-
-## Future Considerations
-
-This unified structure makes future enhancements easier:
-- Easier to add per-user quotas
-- Simpler backup/restore logic
-- Better support for user-specific configuration
-- Cleaner codebase with consistent patterns
-
-## Documentation Updates
-
-- `MIGRATION.md` - Detailed migration guide
-- `CHANGES_SUMMARY.md` - This file
-- Code comments updated to reflect new structure