Feature/python api image discovery (#34)

* Expose chat.analyzeMediaImage in Python API for batch image metadata generation

* Fix updateMedia losing linkedPostIds by reading existing sidecar before overwriting

* Also preserve author from sidecar when DB value is null (data drift)

* Extend MetadataDiffEngine to cover media, scripts, and templates

* Redesign MetadataDiffPanel: item-first view with field pills, filtering, and per-item multi-field diffs

* Fix task:progress startsWith crash (taskId not id) and nested button violation in field pills

* Populate field diffs for file-missing items and show fileMissing badge in UI

* feat: extended meta diff

* feat: meta diff als reconstructs orphans

* chore: updated documentation

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Co-authored-by: hugo <hugoms@me.com>

src/main/main.ts

@@ -920,7 +920,7 @@ app.whenReady().then(async () => {
   const tagEngine = new TagEngine(postEngine);
   const scriptEngine = new ScriptEngine(noopNotifier);
   const templateEngine = new TemplateEngine(noopNotifier);
-  const metadataDiffEngine = new MetadataDiffEngine(postEngine);
+  const metadataDiffEngine = new MetadataDiffEngine(postEngine, mediaEngine, scriptEngine, templateEngine);
   const publishEngine = new PublishEngine();
   const gitEngine = new GitEngine();
   const gitApiAdapter = new GitApiAdapter(gitEngine, projectEngine);