chore(cli): remove broken build caching (#1042)

The agent build caching never worked - BUILD-META comments were
never written to output files, so every build acted like --force.

Since building all 29 agents takes ~300ms, caching provided no
meaningful benefit. Removed ~190 lines of dead code including
checkIfNeedsRebuild, checkBuildStatus, buildMetadataComment,
and the --force flag.

Co-authored-by: Brian <bmadcode@gmail.com>

tools/cli/lib/yaml-xml-builder.js

@@ -232,21 +232,6 @@ class YamlXmlBuilder {
     return xml;
   }
 
-  /**
-   * Build metadata comment
-   */
-  buildMetadataComment(metadata) {
-    const lines = ['<!-- BUILD-META', `  source: ${metadata.sourceFile || 'unknown'} (hash: ${metadata.sourceHash || 'unknown'})`];
-
-    if (metadata.customizeFile) {
-      lines.push(`  customize: ${metadata.customizeFile} (hash: ${metadata.customizeHash || 'unknown'})`);
-    }
-
-    lines.push(`  built: ${new Date().toISOString()}`, `  builder-version: ${metadata.builderVersion || '1.0.0'}`, '-->\n');
-
-    return lines.join('\n');
-  }
-
   /**
    * Build persona XML section
    */