refactor: pre-release uses CLI version_bump.php instead of inline shell math

Delegates version bumping to moko-platform CLI tools:
- version_bump.php (patch default, --minor for RC)
- version_set_platform.php (stability suffix)
- version_check.php (consistency)

This keeps the workflow thin and the logic in the shared CLI.

Authored-by: Moko Consulting
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.mokogitea/workflows/pre-release.yml

@@ -96,36 +96,23 @@ jobs:
             release-candidate)  SUFFIX="-rc";    TAG="release-candidate" ;;
           esac
 
-          # Read current version (bump already handled by push workflow)
-          VERSION=$(php ${MOKO_CLI}/version_read.php --path . 2>/dev/null)
-          [ -z "$VERSION" ] && VERSION="00.00.01"
-
-          # Strip any existing suffix from version before applying stability
-          VERSION=$(echo "$VERSION" | sed 's/-\(dev\|alpha\|beta\|rc\)$//')
-
-          # Dev/alpha/beta: bump patch so each build gets a unique version
-          # RC: consolidate to next minor (02.33.xx → 02.34.00)
-          MAJOR=$(echo "$VERSION" | cut -d. -f1)
-          MINOR=$(echo "$VERSION" | cut -d. -f2)
-          PATCH=$(echo "$VERSION" | cut -d. -f3)
+          # Bump version via CLI: patch for dev/alpha/beta, minor for RC
           case "$STABILITY" in
-            development|alpha|beta)
-              PATCH=$(printf "%02d" $((10#$PATCH + 1)))
-              VERSION="${MAJOR}.${MINOR}.${PATCH}"
-              ;;
-            release-candidate)
-              MINOR=$(printf "%02d" $((10#$MINOR + 1)))
-              VERSION="${MAJOR}.${MINOR}.00"
-              ;;
+            release-candidate) BUMP="minor" ;;
+            *)                 BUMP="patch" ;;
           esac
 
+          php ${MOKO_CLI}/version_bump.php --path . $([ "$BUMP" = "minor" ] && echo "--minor") 2>/dev/null || true
+
+          # Set stability suffix and verify consistency
+          VERSION=$(php ${MOKO_CLI}/version_read.php --path . 2>/dev/null || echo "00.00.01")
+          VERSION=$(echo "$VERSION" | sed 's/-\(dev\|alpha\|beta\|rc\)$//')
+
           php ${MOKO_CLI}/version_set_platform.php \
             --path . --version "$VERSION" --branch "${{ github.ref_name }}" --stability "$STABILITY" 2>/dev/null || true
-
-          # Verify version consistency across all files
           php ${MOKO_CLI}/version_check.php --path . --fix 2>/dev/null || true
 
-          # Update VERSION variable with suffix
+          # Append suffix for output
           if [ -n "$SUFFIX" ]; then
             VERSION="${VERSION}${SUFFIX}"
           fi