feat(ui): finish the workspace-sessions plan — tool filter, session search, explicit Resume

- Sidebar: a tool filter (shown once workspaces of two tools exist, kept in
  agenthub.sidebar.projects → tool; reordering under it keeps the hidden
  workspaces' places), and search that also finds a workspace by one of its
  session names, showing only the matching sessions.
- Workspace home: the repository it belongs to (root, main branch, worktree
  count) under the title, and each recent's cost.
- Transcript page: an explicit Resume for a Claude session started in a
  workspace's own folder (SessionResumeButton). It warns that a resume re-reads
  the whole transcript, re-reads the live panes, then starts in the first free
  pane and opens it; a live session offers Open pane instead.

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

@@ -329,13 +329,24 @@
   "sessions.empty": "No sessions in this workspace yet",
   "sessions.resume": "Resume",
   "sessions.open": "Open",
+  "resume.openPane": "Open pane",
+  "resume.hint": "Resume this session in a workspace pane — re-reads its whole transcript into context",
+  "resume.title": "Resume this session?",
+  "resume.body": "Resuming re-reads the session's whole transcript into the model's context, so its next turns pay for all of it again. It opens in the first free pane of {{workspace}}. To only read it, stay on this page.",
+  "resume.confirm": "Resume session",
   "sessions.search": "Filter sessions…",
   "tree.title": "Workspaces",
   "tree.search": "Search workspaces and sessions",
+  "tree.toolFilter": "Filter by tool",
+  "tree.allTools": "All tools",
   "tree.newSession": "New session",
   "tree.noSessions": "No sessions yet",
   "tree.transcriptHint": "No live pane — opens the transcript",
   "home.breadcrumb": "Workspaces",
+  "home.repoRoot": "Repository root",
+  "home.mainBranch": "Main worktree's branch",
+  "home.worktreeCount_one": "{{count}} worktree",
+  "home.worktreeCount_other": "{{count}} worktrees",
   "home.placeholder": "How can I help you today?",
   "home.start": "Start",
   "home.allBusy": "All four panes of this workspace are busy — stop one before starting another session.",