v0.18.0 — floating terminals, shell sessions, and better workspace launches

This release turns a round of real user feedback into a more direct day-to-day
board: terminals no longer cover the fleet, standalone shells and visible setup
commands make workspace bring-up useful beyond Claude itself, dead cards can be
dismissed one at a time, and stalled launches now show what was actually left on
the pane. Repository spawns also learn a durable default organization, including
Coder's textemma seed and GitLab subgroup inference.

Added

• Floating live terminals. A terminal now opens in a draggable, resizable
  window above the board, can be minimized to a dock chip without dropping its
  WebSocket, remembers its position, and falls back to the full-screen viewer on
  small/touch displays. The terminal keeps keyboard focus visually explicit so
  board permission shortcuts cannot be mistaken for input sent to the pane.
• In-board help. A ? overlay documents keyboard shortcuts, card and header
  actions, and orchestrator command grammar. Compose now includes compact,
  clickable examples for broadcast, assign, ticket, and name commands.
• Standalone shell sessions. Spawn a shell without Claude, or open a new shell
  in any card's workspace. Shell cards remain terminal-first, can be killed
  directly, never receive fleet mail, and are excluded from orchestrator routing.
• Visible setup commands before Claude starts. Repo and directory spawns can
  run an explicit setup command in the pane after materialization and before
  launching Claude. Per-repository defaults can be saved; a failing setup remains
  visible and prevents Claude from starting, while revive intentionally skips
  setup for an already-materialized workspace.
• Default organizations for bare repository names. A bare repo can resolve
  through a persisted or environment-provided namespace. Coder workspaces seed
  textemma; multi-segment group paths infer GitLab when no host was supplied;
  explicit hosts still win or fail loudly. Namespace validation prevents URL and
  scp delimiters from changing the requested clone target.
• Registration-stall diagnostics. When a spawned pane never registers, Fleet
  Deck captures a redacted, UTF-8-safe, byte-bounded tail of the pane and exposes
  it in the card and Drawer, making setup errors, trust prompts, and environment
  failures diagnosable without opening the terminal.
• Per-card dismissal. Individual offline sessions can be removed without
  clearing every tombstone. Revivable cards require a second confirmation, and
  dismissal keeps their worktrees available in the Worktrees view.

Fixed

• Copy shortcuts no longer open Compose. Modified key chords are excluded
  from board hotkeys, so Command/Ctrl+C and ordinary copy/paste work normally.
• A vanished pane is reported as an ended agent, not a refused viewer. The
  terminal WebSocket sends a clean exit frame and triggers liveness reconciliation
  when the database still says live but tmux has already removed the pane.
• Cold-start hooks authenticate the first registration. SessionStart now
  rereads the bearer token minted by a daemon it just started, so the first card
  and roster brief are no longer silently lost on a fresh home.
• Shell/setup isolation stays inside Fleet Deck. remain-on-exit is scoped to
  the fleet tmux session rather than the shared server, shell sessions cannot
  become mail or auto-assignment black holes, and the liveness watchdog recognizes
  legitimate shell/setup phases instead of condemning them as dead Claude panes.
• The release smoke test is genuinely isolated. It uses a unique temporary
  home, dedicated port and tmux socket, authenticated hooks, exactly two workers,
  process-group cleanup, verified graceful daemon shutdown, and never stops the
  live board on port 4711.

Full changelog