fix(tmux-manager): use '|' separator in reconcileSessions (#71)

* fix(tmux-manager): use '|' separator in reconcileSessions

Under non-tty execution contexts (launchd on macOS, systemd without TTY),
tmux emits '\t' in FORMAT strings as the literal two characters `\` + `t`
rather than as a tab. The parser's `line.indexOf('\t')` (a real tab char)
therefore never matches, `activeSessions` stays empty, `reconcileSessions`
returns `alive: []` / `discovered: []`, and `cleanupStaleSessions()` wipes
every entry in `state.json` — even though the underlying tmux sessions are
still alive. On the next startup the user sees an empty session list.

The bug reproduces reliably when codeman is launched via a user LaunchAgent
or a systemd unit without `TTYPath`. Interactive `npm run dev` hides it
because tmux's format parser does interpret `\t` when stdout is a TTY.

Fix: use `|` as the separator. tmux passes it through verbatim in every
environment, and `|` is not a valid tmux session-name character so it
cannot collide with the codeman-<uuid> / claudeman-<uuid> naming scheme.

* test(tmux-manager): cover parsePaneList separator contract

Extract the inline pane-list parser from `reconcileSessions` into an
exported `parsePaneList()` helper plus `PANE_LIST_SEP` / `PANE_LIST_FORMAT`
constants, so the '|' separator contract can be unit-tested directly.

The new tests lock in:
- Well-formed parsing into name -> pid Map
- Empty / blank-line / missing-separator handling
- Non-numeric pid and empty-name rejection
- A literal `\t` (backslash + t) in the input is NOT treated as a
  delimiter — guards against the launchd/systemd regression that
  motivated PR #71.
- Splitting on the first separator only.

No behavior change in `reconcileSessions`; the body now delegates to the
helper.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Teigen <teigen@TeigendeMac-mini.local>
Co-authored-by: arkon <arkon.85@hotmail.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>