why: libtmux 0.60.0 completes tmux 3.7 feature parity, adding
floating panes, typed 3.7 options, new pane format variables, and
new command flags. Every 3.7-only surface is version-gated, so tmux
3.2a-3.6 keep working unchanged. The bump is purely additive for
tmuxp, requiring no code or test migration.

what:
- Bump libtmux ~=0.59.0 -> ~=0.60.0 in pyproject.toml
- Update uv.lock to libtmux 0.60.0 from PyPI

libtmux 0.60.0 (2026-06-28):
- Floating panes via Window.new_pane()/Pane.new_pane() (#694)
- Typed tmux 3.7 server/session/window/pane options (#694)
- New tmux 3.7 pane format variables on Pane (#694)
- New tmux 3.7 command flags on capture_pane/split/kill and more (#694)

Release: https://github.com/tmux-python/libtmux/releases/tag/v0.60.0
Changelog: https://libtmux.git-pull.com/history.html#libtmux-0-60-0-2026-06-28

why: Record the libtmux ~=0.59.0 -> ~=0.60.0 floor bump under the
1.72.0 unreleased block. The release lead paragraph and version
header are added by the maintainer at tag time, not by this PR.

what:
- Record the libtmux ~=0.59.0 -> ~=0.60.0 floor bump under Dependencies
- Note tmux 3.7 feature parity (floating panes, typed options, new
  pane format vars and command flags) under What's new, scoped to the
  user-visible libtmux surface without internal mechanics

Raise the libtmux floor to 0.60.0, which completes tmux 3.7 feature
parity at the library layer tmuxp builds on. Every new surface —
floating panes, typed 3.7 options, new pane format variables, and new
command flags — is additive and version-gated, so tmuxp behavior and
tmux 3.2a-3.6 support are unchanged. The bump is purely additive: no
tmuxp code or test migration was required.

- **Dependency:** libtmux ~=0.59.0 -> ~=0.60.0; uv.lock regenerated
- **Docs:** changelog entry under the 1.72.0 unreleased block

libtmux 0.60.0 (2026-06-28):
- Floating panes via Window.new_pane() / Pane.new_pane()
- Typed tmux 3.7 server, session, window, and pane options
- New tmux 3.7 pane format variables on Pane
- New 3.7 command flags on capture_pane, split, Session.kill, and more

Release: https://github.com/tmux-python/libtmux/releases/tag/v0.60.0
Changelog: https://libtmux.git-pull.com/history.html#libtmux-0-60-0-2026-06-28

Minor release bumping the libtmux floor to 0.60.0, which completes tmux
3.7 feature parity at the library layer tmuxp builds on (#1065). The new
libtmux capabilities — floating panes, typed tmux 3.7 options, new pane
format variables, and new command flags — are reachable through tmuxp's
Python API and tmux shell; the YAML workspace format and tmux 3.2a-3.6
support are unchanged.