Enhance logging and timing in CLI and session operations

- Updated the `_print_checks` function to replace console prints with logging functions for better traceability.
- Introduced timing functionality in the `doctor`, `dry_run`, and `up` functions to log the duration of preflight checks.
- Modified the `wait_ssh` function to accept a logging callback, improving SSH wait feedback.
- Enhanced the `mark` method in `PhaseTimes` to log phase durations, aiding in performance analysis.
- Updated various remote scripts to ensure error messages are printed to stderr for better error handling.

src/gpu_rent/tunnel.py

@@ -144,7 +144,7 @@ def _recover_unshelve(cfg: Config, log: Log) -> str:
     state.phase = "ready_tunneled"
     save_state(state)
     log(f"жду SSH на {ip}…")
-    wait_ssh(cfg, ip, timeout=420)
+    wait_ssh(cfg, ip, timeout=420, log=log)
     return ip