feat: presentation defaults + scheduler active-only

Add Settings → Events (Presentations) defaults (interval, page-progress,
auto-progress) persisted via /api/system-settings
Seed defaults in init_defaults.py (10/true/true)
Add Event.page_progress and Event.auto_progress (Alembic applied)
CustomEventModal applies defaults on create and saves fields
Scheduler publishes only currently active events per group, clears retained
topics when none, normalizes times to UTC; include flags in payloads
Docs: update README, copilot instructions, and DEV-CHANGELOG
If you can split the commit, even better

feat(dashboard): add presentation defaults UI
feat(api): seed presentation defaults in init_defaults.py
feat(model): add Event.page_progress and Event.auto_progress
feat(scheduler): publish only active events; clear retained topics; UTC
docs: update README and copilot-instructions
chore: update DEV-CHANGELOG

TECH-CHANGELOG.md

@@ -0,0 +1,67 @@
+
+# TECH-CHANGELOG
+
+
+
+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`.
+
+---
+
+## 2025.1.0-alpha.11 (2025-10-16)
+
+---
+
+## 2025.1.0-alpha.11 (2025-10-16)
+- ✨ Settings page: New tab layout (Syncfusion) with role-based visibility – Tabs: 📅 Academic Calendar, 🖥️ Display & Clients, 🎬 Media & Files, 🗓️ Events, ⚙️ System.
+- 🛠️ Settings (Technical): API calls now use relative /api paths via the Vite proxy (prevents CORS and double /api).
+- 📖 Docs: README updated for settings page (tabs) and system settings API.
+
+## 2025.1.0-alpha.10 (2025-10-15)
+- 🔐 Auth: Login and user management implemented (role-based, persistent sessions).
+- 🧩 Frontend: Syncfusion SplitButtons integrated (react-splitbuttons) and Vite config updated for pre-bundling.
+- 🐛 Fix: Import error ‘@syncfusion/ej2-react-splitbuttons’ – instructions added to README (optimizeDeps + volume reset).
+
+## 2025.1.0-alpha.9 (2025-10-14)
+- ✨ UI: Unified deletion workflow for appointments – all types (single, single instance, entire series) handled with custom dialogs.
+- 🔧 Frontend: Syncfusion RecurrenceAlert and DeleteAlert intercepted and replaced with custom dialogs (including final confirmation for series deletion).
+- 📖 Docs: README and Copilot instructions expanded for deletion workflow and dialog handling.
+
+## 2025.1.0-alpha.8 (2025-10-11)
+- 🎨 Theme: Migrated to Syncfusion Material 3; centralized CSS imports in main.tsx
+- 🧹 Cleanup: Tailwind CSS completely removed (packages, PostCSS, Stylelint, config files)
+- 🧩 Group management: "infoscreen_groups" migrated to Syncfusion components (Buttons, Dialogs, DropDownList, TextBox); improved spacing
+- 🔔 Notifications: Unified toast/dialog wording; last alert usage replaced
+- 📖 Docs: README and Copilot instructions updated (Material 3, centralized styles, no Tailwind)
+
+## 2025.1.0-alpha.7 (2025-09-21)
+- 🧭 UI: Period selection (Syncfusion) next to group selection; compact layout
+- ✅ Display: Badge for existing holiday plan + counter ‘Holidays in view’
+- 🛠️ API: Endpoints for academic periods (list, active GET/POST, for_date)
+- 📅 Scheduler: By default, no scheduling during holidays; block display like all-day event; black text color
+- 📤 Holidays: Upload from TXT/CSV (headless TXT uses columns 2–4)
+- 🔧 UX: Switches in a row; dropdown widths optimized
+
+## 2025.1.0-alpha.6 (2025-09-20)
+- 🗓️ NEW: Academic periods system – support for school years, semesters, trimesters
+- 🏗️ DATABASE: New 'academic_periods' table for time-based organization
+- 🔗 EXTENDED: Events and media can now optionally be linked to an academic period
+- 📊 ARCHITECTURE: Fully backward-compatible implementation for gradual rollout
+- ⚙️ TOOLS: Automatic creation of standard school years for Austrian schools
+
+## 2025.1.0-alpha.5 (2025-09-14)
+- Backend: Complete redesign of backend handling for group assignments of new clients and steps for changing group assignment.
+
+## 2025.1.0-alpha.4 (2025-09-01)
+- Deployment: Base structure for deployment tested and optimized.
+- FIX: Program error when switching view on media page fixed.
+
+## 2025.1.0-alpha.3 (2025-08-30)
+- NEW: Program info page with dynamic data, build info, and changelog.
+- NEW: Logout functionality implemented.
+- FIX: Sidebar width corrected in collapsed state.
+
+## 2025.1.0-alpha.2 (2025-08-29)
+- INFO: Analysis and display of used open-source libraries.
+
+## 2025.1.0-alpha.1 (2025-08-28)
+- Initial project setup and base structure.