v0.4.0

The observation epic completed: the status bar tickers who's waiting in other projects (tmux
itself does the scheduling — no daemon), the explorer notifies when a pinned project's agent
wants you (its memory stored in the tmux server, like everything else), and the how-it-works
doc explains the whole model for tmux newcomers. Hardened by a Codex review (two findings,
both fixed pre-release) — a rhythm now codified in .codex-review.

Added

• Cross-project ticker in the status bar. Every managed terminal's status bar now shows,
  on the right, who's waiting for you in other projects (B: planner⚠) — empty when nobody
  is. tmux itself re-runs the check on its redraw schedule (~15s): no daemon, no stored state.
  Applies to sessions created/adopted from now on. Closes #4.

• macOS notifications when an agent starts waiting. The explorer's 10-second poll now
  remembers each participant's last state (as a tmux window option — the memory lives in the
  server too) and posts a notification on the transition into waiting — for pinned
  projects only; everything else stays glanceable in the menu, which now also carries the
  ⚠/○ state marks. Closes #5.

• "How foreman works" doc. docs/how-it-works.md — the terminal-server model, foreman's
  thin semantic layer, where state lives, and snapshot-vs-memory, written for readers new to
  tmux. Linked from the README, whose roadmap now reflects the completed observation epic.
  Closes #24.

Fixed

• One classifier for all observation surfaces. The ticker used a cheaper title-only check,
  so a titleless agent at a y/n prompt could show waiting⚠ in foreman list and trigger a
  notification while missing from the ticker. All three surfaces now share the full classifier —
  the capture fallback only ever runs for titleless agent windows, which are rare. Found by
  Codex review. Closes #38.

• The ticker survives the binary moving. The status-bar command now prefers the
  PATH-resolved foreman over the running executable's path (which can be a go run temp dir
  or scratch build), and session styling is re-stamped on go and pin — so existing sessions
  self-heal toward the binary you actually use. Found by Codex review. Closes #37.

• Explorer: clicking a participant is injection-safe. The fm … go … command reaches
  AppleScript as an argument (never spliced into the script) and every shell argument is
  quoted — so spaces, quotes, or metacharacters in project/role names or the fm path open the
  right terminal instead of breaking or executing something else. Found by Codex review.
  Closes #30.

• Explorer: Refresh can't race the timer anymore. The 10-second timer and the Refresh menu
  item both triggered menu rebuilds concurrently — two at once could close the same channel
  twice (a crash) or mutate the menu mid-rebuild. All rebuilds now run on one goroutine; Refresh
  just asks it to go. Found by Codex review. Closes #31.