ci: group cloud, desktop, mobile in one release workflow (#12802)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Introduced new workflows for preparing releases, cloud deployment, and
coordinated multi-platform releases with manual approval for stable
Docker images.
- Added a reusable action to output app version, Git hash, and build
type for consistent release metadata.

- **Refactor**
- Simplified and unified input handling across workflows, requiring
explicit version and build metadata inputs.
- Updated release workflows (desktop, mobile, cloud) to use direct
inputs instead of deriving values internally.

- **Chores**
- Removed several legacy and redundant workflows, including automatic
deployment, release, label checking, auto-assign, and Helm chart
publishing.
- Deleted jobs and workflows related to self-hosted image builds, mobile
app test builds, and previous deployment processes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

.github/actions/prepare-release/action.yml

@@ -0,0 +1,42 @@
+name: Prepare Release
+description: 'Prepare Release'
+outputs:
+  APP_VERSION:
+    description: 'App Version'
+    value: ${{ steps.get-version.outputs.APP_VERSION }}
+  GIT_SHORT_HASH:
+    description: 'Git Short Hash'
+    value: ${{ steps.get-version.outputs.GIT_SHORT_HASH }}
+  BUILD_TYPE:
+    description: 'Build Type'
+    value: ${{ steps.get-version.outputs.BUILD_TYPE }}
+runs:
+  using: 'composite'
+  steps:
+    - name: Get Version
+      id: get-version
+      shell: bash
+      run: |
+        GIT_SHORT_HASH=$(git rev-parse --short HEAD)
+        if [ "${{ github.ref_type }}" == "tag" ]; then
+          APP_VERSION=$(echo "${{ github.ref_name }}" | sed 's/^v//')
+        else
+          PACKAGE_VERSION=$(node -p "require('./package.json').version")
+          APP_VERSION=$PACKAGE_VERSION-canary.$GIT_SHORT_HASH
+        fi
+        if [[ "$APP_VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+          BUILD_TYPE=stable
+        elif [[ "$APP_VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+-beta\.[0-9]+$ ]]; then
+          BUILD_TYPE=beta
+        elif [[ "$APP_VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+-canary\.[0-9a-f]+$ ]]; then
+          BUILD_TYPE=canary
+        else
+          echo "Error: unsupported version string: $APP_VERSION" >&2
+          exit 1
+        fi
+        echo $APP_VERSION
+        echo $GIT_SHORT_HASH
+        echo $BUILD_TYPE
+        echo "APP_VERSION=$APP_VERSION" >> "$GITHUB_OUTPUT"
+        echo "GIT_SHORT_HASH=$GIT_SHORT_HASH" >> "$GITHUB_OUTPUT"
+        echo "BUILD_TYPE=$BUILD_TYPE" >> "$GITHUB_OUTPUT"