add migration plan

migration.md

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+# Migration Plan: Bare-Metal Nextcloud to Docker
+
+Fresh Docker install with manual re-upload via Nextcloud client.
+Old setup: bare-metal Nextcloud (MySQL) at `t-gstone.de/nextcloud`.
+New setup: Docker-based Nextcloud (PostgreSQL) at `nextcloud.t-gstone.de`.
+
+## Before Migration
+
+### 1. Export Calendars and Contacts from Old Instance
+
+These live in the database and won't carry over automatically:
+
+- **Calendars**: Go to Calendar app > Settings (bottom-left) > click `...` next to each calendar > Export (downloads `.ics`)
+- **Contacts**: Go to Contacts app > Settings (bottom-left) > click `...` next to each address book > Export (downloads `.vcf`)
+
+Also export any other DB-only app data you care about (Notes, Deck boards, Bookmarks, etc.).
+
+### 2. Create DNS Record
+
+Add an A record for `nextcloud.t-gstone.de` pointing to your VPS IP. Do this early so DNS propagates.
+
+### 3. Deploy Fresh Docker Setup
+
+```bash
+# Clone repo on VPS, configure .env files
+cp .env.example .env          # set DOMAIN and DATA_ROOT
+cp nextcloud/.env.example nextcloud/.env  # set DB creds, admin user, redis password
+cp gitea/.env.example gitea/.env
+cp monitoring/.env.example monitoring/.env
+
+# Deploy
+./scripts/deploy.sh
+```
+
+Verify the fresh instance works at `https://nextcloud.t-gstone.de`.
+
+### 4. Re-Upload Files via Nextcloud Client
+
+- Install the Nextcloud desktop client
+- Point it to `https://nextcloud.t-gstone.de`
+- Sync your files from your local machine
+
+### 5. Re-Import Calendars and Contacts
+
+- **Calendars**: Calendar app > Settings > Import > select the `.ics` files
+- **Contacts**: Contacts app > Settings > Import > select the `.vcf` files
+
+### 6. Verify
+
+- [ ] Files are complete and accessible
+- [ ] Calendars show all events
+- [ ] Contacts are intact
+- [ ] Sharing works
+- [ ] Mobile apps connect successfully
+
+### 7. Decommission Old Instance
+
+Once satisfied:
+
+1. Shut down old bare-metal Nextcloud
+2. Optionally redirect `t-gstone.de/nextcloud` to `nextcloud.t-gstone.de`
+3. Update all Nextcloud clients on your devices to the new URL
+4. Keep the old data/DB dump as a backup for a few weeks before deleting
+
+## What Won't Carry Over (DB-only data)
+
+These are stored in the MySQL database, not in files. Export before shutting down the old instance if you need them:
+
+- Calendars / Contacts (CalDAV/CardDAV) — export as `.ics`/`.vcf`
+- Share links and shared folder structures
+- Notes, Deck boards, Bookmarks, Talk history
+- App settings and configurations
+- Activity log / file versioning metadata