why: Config-backed servers should start and load config without breaking liveness checks.
what:
- run first command with -f via tmux bin when server is down
- align rust-backend server helpers to new signature
- refine rust helper error handling and typing

why: We need per-test timing breakdowns to locate slow paths.
what:
- emit JSONL spans for libtmux rust backend calls
- surface trace summary in pytest terminal output
- capture server is_alive/require_server timing

why: Need per-command context when tracing slow rust backend calls.
what:
- include socket/config/connection_kind on rust_server_cmd span

why: Control-mode refresh hints should not trigger background view capture during tests.
what:
- Subscribe with capture_view=false for rust control-mode test server

why: Keep libtmux spans connected to vibe-tmux and propagate traceparent into Rust backend calls.
what:
- Add traceparent scope helper and current-span extraction fallback
- Wrap rust backend calls with traceparent context in common/server paths

why: The rebase onto current master surfaced a missing contextlib
import from conflict resolution, and the branch predated master's
current lint/type gate (docstrings, typed otel shims, import
ordering, line lengths).

what:
- Import contextlib in server.py for the otel fallback shim
- Type the start_span/traceparent_scope fallback shims to match
  libtmux.otel's signatures and add docstrings
- Annotate and reformat libtmux/otel.py; use contextlib.suppress
- Add mypy overrides for optional opentelemetry/vibe_tmux imports
- Keep the pytest plugin's dynamic _rust_refresh via setattr with a
  B010 suppression so mypy doesn't require a typed attribute
- Apply ruff autofixes (import sort, nested with, formatting)