feat: add Ressourcen timeline view with group ordering (alpha.14)

- New timeline page showing all groups and active events in parallel
- Group order API endpoints with persistence (GET/POST /api/groups/order)
- Customizable group ordering with visual controls
- Fix CSS and TypeScript lint errors
- Update documentation and bump version to 2026.1.0-alpha.14

TECH-CHANGELOG.md

@@ -5,6 +5,57 @@
 
 This changelog documents technical and developer-relevant changes included in public releases. For development workspace changes, see DEV-CHANGELOG.md. Not all changes here are reflected in the user-facing changelog (`program-info.json`), and not all UI/feature changes are repeated here. Some changes (e.g., backend refactoring, API adjustments, infrastructure, developer tooling, or internal logic) may only appear in TECH-CHANGELOG.md. For UI/feature changes, see `dashboard/public/program-info.json`.
 
+## 2026.1.0-alpha.14 (2026-01-28)
+- 🗓️ **Ressourcen Page (Timeline View)**:
+	- New frontend page: `dashboard/src/ressourcen.tsx` (357 lines) – Parallel timeline view showing active events for all room groups
+	- Uses Syncfusion ScheduleComponent with TimelineViews module for resource-based scheduling
+	- Compact visualization: 65px row height per group, dynamically calculated total container height
+	- Real-time event loading: Fetches events per group for current date range on mount and view/date changes
+	- Timeline modes: Day (default) and Week views with date range calculation
+	- Color-coded event bars: Uses `getGroupColor()` from `groupColors.ts` for group theme matching
+	- Displays first active event per group with type, title, and time window
+	- Filters out "Nicht zugeordnet" group from timeline display
+	- Resource mapping: Each group becomes a timeline resource row, events mapped via `ResourceId`
+	- Syncfusion modules: TimelineViews, Resize, DragAndDrop injected for rich interaction
+- 🎨 **Ressourcen Styling**:
+	- New CSS file: `dashboard/src/ressourcen.css` (178 lines) with modern Material 3 design
+	- Fixed CSS lint errors: Converted `rgba()` to modern `rgb()` notation with percentage alpha values (`rgb(0 0 0 / 10%)`)
+	- Removed unnecessary quotes from font-family names (Roboto, Oxygen, Ubuntu, Cantarell)
+	- Fixed CSS selector specificity ordering (`.e-schedule` before `.ressourcen-timeline-wrapper .e-schedule`)
+	- Card-based controls layout with shadow and rounded corners
+	- Group ordering panel with scrollable list and action buttons
+	- Responsive timeline wrapper with flex layout
+- 🔌 **Group Order API**:
+	- New backend endpoints in `server/routes/groups.py`:
+		- `GET /api/groups/order` – Retrieve saved group display order (returns JSON with `order` array of group IDs)
+		- `POST /api/groups/order` – Persist group display order (accepts JSON with `order` array)
+	- Order persistence: Stored in `system_settings` table with key `group_display_order` (JSON array of integers)
+	- Automatic synchronization: Missing group IDs added to order, removed IDs filtered out
+	- Frontend integration: Group order panel with drag up/down buttons, real-time reordering with backend sync
+- 🖥️ **Frontend Technical**:
+	- State management: React hooks with unused setters removed (setTimelineView, setViewDate) to resolve lint warnings
+	- TypeScript: Changed `let` to `const` for immutable end date calculation
+	- UTC date parsing: Uses parseUTCDate callback to append 'Z' and ensure UTC interpretation
+	- Event formatting: Capitalizes first letter of event type for display (e.g., "Website - Title")
+	- Loading state: Shows loading indicator while fetching group/event data
+	- Schedule height: Dynamic calculation based on `groups.length * 65px + 100px` for header
+- 📖 **Documentation**:
+	- Updated `.github/copilot-instructions.md`:
+		- Added Ressourcen page to "Recent changes" section (January 2026)
+		- Added `ressourcen.tsx` and `ressourcen.css` to "Important files" list
+		- Added Groups API order endpoints documentation
+		- Added comprehensive Ressourcen page section to "Frontend patterns"
+	- Updated `README.md`:
+		- Added Ressourcen page to "Pages Overview" section with feature details
+		- Added `GET/POST /api/groups/order` to Core Resources API section
+	- Bumped version in `dashboard/public/program-info.json` to `2026.1.0-alpha.14` with user-facing changelog
+
+Notes for integrators:
+- Group order API returns JSON with `{ "order": [1, 2, 3, ...] }` structure (array of group IDs)
+- Timeline view automatically filters "Nicht zugeordnet" group for cleaner display
+- CSS follows modern Material 3 color-function notation (`rgb(r g b / alpha%)`)
+- Syncfusion ScheduleComponent requires TimelineViews, Resize, and DragAndDrop modules injected
+
 ## 2025.1.0-beta.1 (TBD)
 - 🔐 **User Management & Role-Based Access Control**:
 	- Backend: Implemented comprehensive user management API (`server/routes/users.py`) with 6 endpoints (GET, POST, PUT, DELETE users + password reset).