feat(lanes,run,pricing): Changes sidebar editor, staged groups, image drop, auto pricing

- Changes panel at full screen: the whole Files view (finder, expand-all,
  tree) becomes a left sidebar and the Files tab is dropped; a working-copy
  file opens straight into the editor (Save/Cancel live once the text
  differs, Cancel restores it, Whole file toggles back to the diff), and the
  page is height-locked so the editor no longer collapses with no live run.
- Overview splits into Staged Changes / Changes groups in the work range.
- A changed file's whole tree row takes its status tint.
- Drag an image onto the lane terminal: POST /api/run/drop-image saves it
  (png/jpeg/gif/webp, random name, 0600, pruned after a day) and the path
  is pasted into the pane, which is how claude attaches it.
- Claude Opus 5.5 gets its own pricing row (4/20/0.2/5/8, fast 8/40);
  claude-opus-5% had been pricing it as Opus 5.
- server/lib/pricing-sync.js: a model family used in token_usage with no
  row of its own is inserted from LiteLLM's public price list, never
  updated; off with AGENTHUB_PRICING_SYNC=0. repo-links allows exactly
  that one third-party GitHub raw URL.

client/src/lib/api.ts

@@ -1982,6 +1982,14 @@ export const api = {
       if (q) qs.set("q", q);
       return request<{ items: string[] }>(`/run/files?${qs.toString()}`);
     },
+    /** POST /api/run/drop-image - save an image dropped on the terminal on the
+     *  server's machine; the returned path is what gets pasted into the pane. */
+    dropImage: (file: Blob) =>
+      request<{ path: string }>("/run/drop-image", {
+        method: "POST",
+        body: file,
+        headers: { "Content-Type": file.type },
+      }),
     /** POST /api/run - start (or adopt, if already live) a lane's terminal run. */
     start: (args: RunStartArgs) =>
       request<RunHandle>("/run", { method: "POST", body: JSON.stringify(args) }),