Webmail is now Cypht (several accounts in one place) instead of Roundcube

- cypht/: official Cypht 2.13.0 on a SQLite file, served under /webmail/; workflow builds git.necloud.us/nate/hub-cypht
- the hub passes /webmail/ through behind the passkey sign-in and signs in to Cypht for you (CYPHT_PASSWORD)
- provider sign-in pages (Google, Microsoft) open in the whole window and return to the Mail tab; other links open in a new tab
- Gmail / Outlook.com / Office365 OAuth settings (Microsoft permissions patched to the current ones)
- Roundcube removed; README, compose and webmail tests updated

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

.gitea/workflows/build.yml

@@ -21,7 +21,7 @@ jobs:
       - run: node tools/users-test.js   # accounts: private data, tab limits, invites, migration
       - run: node tools/plex-test.js    # Plex sign-in stays signed in and repairs itself
       - run: node tools/player-test.js  # music player: queue, shuffle/repeat, stall recovery
-      - run: node tools/webmail-test.js # the /webmail/ pass-through to Roundcube
+      - run: node tools/webmail-test.js # the /webmail/ pass-through to the bundled webmail (Cypht)
 
       - uses: docker/setup-buildx-action@v3
 
@@ -53,11 +53,11 @@ jobs:
           cache-from: type=registry,ref=git.necloud.us/nate/hub:buildcache
           cache-to: type=registry,ref=git.necloud.us/nate/hub:buildcache,mode=max
 
-      # The webmail container (official Roundcube + the hub's settings)
+      # The webmail container (official Cypht + the hub's settings)
       - id: meta_rc
         uses: docker/metadata-action@v5
         with:
-          images: git.necloud.us/nate/hub-roundcube
+          images: git.necloud.us/nate/hub-cypht
           tags: |
             type=raw,value=latest,enable={{is_default_branch}}
             type=sha,format=short
@@ -65,7 +65,7 @@ jobs:
 
       - uses: docker/build-push-action@v6
         with:
-          context: ./roundcube
+          context: ./cypht
           platforms: linux/amd64
           push: true
           tags: ${{ steps.meta_rc.outputs.tags }}