feat(mod_format): Refactor formatting modules to new BaseFormatter and implement concrete analyze/apply logic

ts/mod_format/formatters/prettier.formatter.ts

@@ -1,5 +1,5 @@
 import { BaseFormatter } from '../classes.baseformatter.js';
-import type { IPlannedChange } from '../interfaces.format.js';
+import type { IPlannedChange, ICheckResult } from '../interfaces.format.js';
 import * as plugins from '../mod.plugins.js';
 import { logger, logVerbose } from '../../gitzone.logging.js';
 
@@ -243,4 +243,53 @@ export class PrettierFormatter extends BaseFormatter {
       arrowParens: 'always',
     });
   }
+
+  /**
+   * Override check() to compute diffs on-the-fly by running prettier
+   */
+  async check(): Promise<ICheckResult> {
+    const changes = await this.analyze();
+    const diffs: ICheckResult['diffs'] = [];
+
+    for (const change of changes) {
+      if (change.type !== 'modify') continue;
+
+      try {
+        // Read current content
+        const currentContent = (await plugins.smartfs
+          .file(change.path)
+          .encoding('utf8')
+          .read()) as string;
+
+        // Skip files without extension (prettier can't infer parser)
+        const fileExt = plugins.path.extname(change.path).toLowerCase();
+        if (!fileExt) continue;
+
+        // Format with prettier to get what it would produce
+        const prettier = await import('prettier');
+        const formatted = await prettier.format(currentContent, {
+          filepath: change.path,
+          ...(await this.getPrettierConfig()),
+        });
+
+        // Only add to diffs if content differs
+        if (formatted !== currentContent) {
+          diffs.push({
+            path: change.path,
+            type: 'modify',
+            before: currentContent,
+            after: formatted,
+          });
+        }
+      } catch (error) {
+        // Skip files that can't be processed
+        logVerbose(`Skipping diff for ${change.path}: ${error.message}`);
+      }
+    }
+
+    return {
+      hasDiff: diffs.length > 0,
+      diffs,
+    };
+  }
 }