refactor: Simplify values.yaml update using exact version matching

Refactor the Update values.yaml step to use exact version matching instead of
regex patterns. This approach is simpler, more reliable, and mirrors the
successful implementation in other Helmcharts (e.g., php-fpm).

Changes:
- Extract full current versions using awk (easier to parse)
- Use exact string replacement: sed 's|old_exact_version|new_exact_version|g'
- Only update if version has actually changed (conditional sed)
- Better error handling with set -e
- Clearer logging of what changed

Benefits:
1. Simpler logic: exact match instead of regex patterns
2. More reliable: no regex pattern matching failures
3. Proven approach: matches successful implementation in other projects
4. Clearer intent: code reads like "if version changed, update it"
5. Better debugging: conditional echo statements show exactly what happened

Flow:
1. Get current full version from values.yaml (e.g., 6.9.0-php8.5-fpm-alpine)
2. Get latest version from Docker Hub (shared variable)
3. If different, replace exact old version with exact new version
4. Report what changed (or didn't change)
5. Determine if WordPress version changed for Chart.yaml update decision

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

.gitea/workflows/image-update-and-release.yaml

@@ -159,7 +159,9 @@ jobs:
         if: steps.check.outputs.update_needed == 'true'
         id: update_values
         run: |
-          # バックアップを作成
+          set -e
+          echo "Updating values.yaml..."
+
           cp values.yaml values.yaml.bak
 
           # 共有変数から最新バージョンを取得
@@ -168,22 +170,29 @@ jobs:
           NGINX_LATEST="${{ steps.nginx.outputs.version }}"
 
           # 現在のバージョンを取得（Chart.yaml更新判定用）
-          CURRENT_WP_BASE=$(grep -A 1 'wordpress:' values.yaml | grep 'tag:' | sed 's/.*tag: "\([^-]*\).*/\1/')
-          CURRENT_NGINX=$(grep -A 1 'nginx:' values.yaml | grep 'tag:' | sed 's/.*tag: "\(.*\)".*/\1/')
+          CURRENT_WP=$(grep -A 3 'wordpress:' values.yaml | grep 'tag:' | awk -F'"' '{print $2}')
+          CURRENT_NGINX=$(grep -A 3 'nginx:' values.yaml | grep 'tag:' | awk -F'"' '{print $2}')
+          CURRENT_WP_BASE=$(echo "$CURRENT_WP" | cut -d'-' -f1)
 
           echo "Current versions:"
-          echo "  WordPress: $CURRENT_WP_BASE"
+          echo "  WordPress: $CURRENT_WP"
           echo "  Nginx: $CURRENT_NGINX"
           echo ""
           echo "Latest versions:"
-          echo "  WordPress: $WP_BASE ($WP_LATEST)"
+          echo "  WordPress: $WP_LATEST"
           echo "  Nginx: $NGINX_LATEST"
 
-          # WordPressのtagを更新（より単純で確実な方法）
-          sed -i "s|tag: \"[0-9.]*-php[0-9.]*-fpm-alpine\"|tag: \"$WP_LATEST\"|" values.yaml
+          # WordPress更新
+          if [ "$CURRENT_WP" != "$WP_LATEST" ]; then
+            sed -i "s|tag: \"${CURRENT_WP}\"|tag: \"${WP_LATEST}\"|g" values.yaml
+            echo "WordPress updated: $CURRENT_WP -> $WP_LATEST"
+          fi
 
-          # Nginxのtagを更新（より単純で確実な方法）
-          sed -i "s|tag: \"[0-9.]*-alpine-perl\"|tag: \"$NGINX_LATEST\"|" values.yaml
+          # Nginx更新
+          if [ "$CURRENT_NGINX" != "$NGINX_LATEST" ]; then
+            sed -i "s|tag: \"${CURRENT_NGINX}\"|tag: \"${NGINX_LATEST}\"|g" values.yaml
+            echo "Nginx updated: $CURRENT_NGINX -> $NGINX_LATEST"
+          fi
 
           # 変更内容を表示
           echo ""
@@ -193,14 +202,14 @@ jobs:
           # 実際に変更されたか確認
           if diff -q values.yaml.bak values.yaml > /dev/null 2>&1; then
             echo "INFO: No changes were made to values.yaml (versions already up to date)"
-            cat values.yaml | grep -A 5 "image:"
             echo "chart_version_update_needed=false" >> $GITHUB_OUTPUT
           else
             echo "Changes detected in values.yaml"
 
             # WordPressバージョンが更新されたか判定（Chart.yaml更新の判定用）
-            if [ "$CURRENT_WP_BASE" != "$WP_BASE" ]; then
-              echo "WordPress version changed: $CURRENT_WP_BASE -> $WP_BASE"
+            WP_NEW_BASE=$(echo "$WP_LATEST" | cut -d'-' -f1)
+            if [ "$CURRENT_WP_BASE" != "$WP_NEW_BASE" ]; then
+              echo "WordPress version changed: $CURRENT_WP_BASE -> $WP_NEW_BASE"
               echo "chart_version_update_needed=true" >> $GITHUB_OUTPUT
             else
               echo "INFO: WordPress version unchanged - only other images updated"
@@ -210,7 +219,7 @@ jobs:
 
           echo ""
           echo "=== Updated values.yaml (image section) ==="
-          grep -A 5 "^image:" values.yaml
+          grep -A 10 "^image:" values.yaml
 
       - name: Increment chart version
         if: steps.update_values.outputs.chart_version_update_needed == 'true'