Add dev/production update channels, clearer Euchre table, bolder Sequence highlight

Update channels
- ci.yml now publishes each green push to dev as a prerelease tagged
  v1.0.<n>-dev, so the dev channel has something to install. Workflow
  artifacts could not serve this: downloading one needs authentication,
  which the app does not have.
- Prereleases specifically, because GitHub's "latest release" endpoint
  skips them — a production install can never be handed a dev build.
  Pull requests build and check but never publish.
- Settings gains a channel picker. The two channels are numbered by
  separate workflow run counters, so versions are only compared within a
  channel; the app reads the -dev suffix in its own versionName to know
  where it stands, and treats a channel change as an explicit switch. The
  screen warns that such a switch can be a downgrade Android will refuse.
- PLG_RELEASE becomes PLG_CHANNEL, naming the channel rather than a flag.

Euchre
- Cards in a trick now sit on the side of the table belonging to whoever
  played them, rotated to face them, labelled You / Left / Partner /
  Right. Previously they were a flat row tagged with seat numbers, which
  made it hard to tell who had played what.
- Bidding says what it will actually do. As dealer the button reads "Pick
  it up" rather than "Order up", since the turn card comes to your hand,
  and a line of explanatory text spells out the consequence either way.

Sequence
- Playable squares get a much heavier outline, scaled off cell size and
  in a fixed amber that reads against a white card, a green corner and a
  chip alike. The old 2dp theme-coloured border was hard to see.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_015qjfMiPUDshdKEUa6vxqzN

.github/workflows/ci.yml

@@ -2,8 +2,14 @@ name: CI
 
 # Pre-merge checks. Runs on the dev branch and on every pull request aimed at
 # dev or main, so breakage is caught before it reaches main and triggers a
-# release. Builds the same debug APK as the release pipeline, but publishes it
-# only as a workflow artifact — no tag, no GitHub Release.
+# release.
+#
+# On a push to dev it also publishes the build as a dev-channel prerelease, so
+# the in-app updater can offer it to anyone who has switched to that channel.
+# Prereleases are used deliberately: GitHub's "latest release" endpoint skips
+# them, so a production-channel user never sees a dev build. Pull requests only
+# build and check — they never publish, which keeps a PR from a fork from
+# shipping anything.
 on:
   push:
     branches: [ dev ]
@@ -11,8 +17,9 @@ on:
     branches: [ main, dev ]
   workflow_dispatch:
 
+# Needed to publish the dev-channel prerelease below.
 permissions:
-  contents: read
+  contents: write
 
 # A newer push to the same branch or PR makes the in-flight run obsolete.
 concurrency:
@@ -23,6 +30,11 @@ jobs:
   build:
     name: Build and check
     runs-on: ubuntu-latest
+    env:
+      # Stamp the APK as a dev-channel build only when this is a real push to
+      # dev. Pull request builds stay unstamped at 1.0.0-dev, since they are
+      # never published and must not claim a channel version.
+      PLG_CHANNEL: ${{ (github.event_name == 'push' && github.ref == 'refs/heads/dev') && 'dev' || '' }}
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -64,3 +76,35 @@ jobs:
             app/build/reports/
           if-no-files-found: ignore
           retention-days: 14
+
+      # Everything below publishes the dev channel, and only ever from a push
+      # to dev that has already built, tested and linted clean above.
+      - name: Stage dev APK
+        id: stage
+        if: github.event_name == 'push' && github.ref == 'refs/heads/dev'
+        run: |
+          set -euo pipefail
+          version="v1.0.${{ github.run_number }}-dev"
+          src="app/build/outputs/apk/debug/app-debug.apk"
+          dest="ProLibertateGames-${version}.apk"
+          cp "$src" "$dest"
+          echo "version=$version" >> "$GITHUB_OUTPUT"
+          echo "apk=$dest" >> "$GITHUB_OUTPUT"
+
+      - name: Publish dev channel prerelease
+        if: github.event_name == 'push' && github.ref == 'refs/heads/dev'
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+          gh release create "${{ steps.stage.outputs.version }}" \
+            "${{ steps.stage.outputs.apk }}" \
+            --repo "${{ github.repository }}" \
+            --target "${{ github.sha }}" \
+            --title "ProLibertateGames ${{ steps.stage.outputs.version }}" \
+            --prerelease \
+            --notes "Automated **dev channel** build from \`${{ github.sha }}\` on \`dev\`.
+
+          Preview build: newer than production, and less tested. Switch to the
+          Dev update channel in Settings to be offered these. Marked as a
+          prerelease so production-channel installs never see it."