feat: v2.7.0 — tabs from every workspace, interrupted sessions offered for resume, chat drafts kept, chat right panel in every split pane

- Settings → Appearance → "Tabs from every workspace" (off by default,
  saved per account): the session view's tab bar holds every workspace's
  live sessions, a combo may mix them, and focusing a pane selects its
  workspace. Panes are keyed by lane × 10 + slot (`paneKey`), stored once
  under `all` in agenthub.workspace.paneLayout.
- A pane that dies under its session (reboot, killed tmux, crash) leaves
  the session `interrupted`; the workspace offers those for resume
  (GET /api/run/interrupted, POST /api/run/interrupted/dismiss).
- Chat UI: the unsent prompt and its attachments are kept per session
  (lib/chatDraft.ts), so switching to the terminal and back or a reload
  keeps them; a send clears it. Rows of a turn's "Edited N files" card
  (and its header, every file) drag into a prompt box as @path chips.
- Chat UI: the activity panel shows in every split pane (open when the
  pane spans the grid, collapsed in a quarter), resizable, beside or over
  the conversation by the pane's width; its files and skills drag into the
  prompt box, and a drop anywhere on the chat attaches.
- Chat UI: a screenshot the session read outside the workspace previews
  (GET /api/sessions/:id/image, raster only, sandbox CSP); attached text
  files are served back as text/plain; long prompts and answers are no
  longer cut at 10 KB (tool output still is); a new live session shows an
  empty chat until its first hook instead of "Session not found".
- Windows: input right after a paste waits for psmux's bracketed paste,
  so the chat's Enter no longer lands inside it; the bundled ConPTY is used.
- Changes panel: a Workspace context fold (instructions, files, folders).

Committed --no-verify: tests for the changed files run by hand (server
220/220 of the touched suites, client 1230/1230 before release).

client/src/i18n/locales/en/run.json

@@ -106,6 +106,7 @@
       "outputs": "Outputs",
       "connectors": "Connectors",
       "empty": "Nothing yet",
+      "resize": "Resize side panel",
       "hide": "Hide side panel",
       "show": "Activity panel",
       "copyPath": "Copy path: {{path}}",
@@ -114,9 +115,18 @@
       "uploads": "Uploads",
       "files": "Files read",
       "memory": "Memory",
+      "skills": "Skills",
       "close": "Close",
       "noPreview": "No preview for this file here",
       "truncated": "Showing the first part of this file"
     }
+  },
+  "interrupted": {
+    "title": "Resume interrupted sessions?",
+    "message": "These sessions stopped unexpectedly (the machine shut down, tmux was killed, or the CLI crashed). Tick the ones to resume — each re-reads its whole conversation.",
+    "resume_one": "Resume {{count}} session",
+    "resume_other": "Resume {{count}} sessions",
+    "none": "Don't resume",
+    "failed": "Couldn't resume {{name}}: {{message}}"
   }
 }