fix(runtime): wait for Caido readiness by deadline

[maxi-maxima]

Summary

• replace the fixed 10-attempt Caido login loop with a monotonic wall-clock deadline
• add STRIX_CAIDO_BOOT_WAIT_S with a 300-second default for slower container hosts
• cap each curl attempt and retry delay to the remaining budget
• document the setting and cover retry success, deadline exhaustion, and env loading

Root cause

Caido readiness was bounded by an attempt count rather than elapsed time. The existing backoff exhausted its ten attempts after roughly 68–73 seconds, so a healthy but slow cold start on a loaded or hosted runner could be reported as a permanent bootstrap failure.

Impact

Slow runners now get a bounded, configurable readiness window while fast failures still stop at the deadline with the elapsed budget and attempt count in the error.

Validation

• uv run pytest tests/test_caido_bootstrap.py tests/test_config_loader.py -q -k "not test_persist_current_sets_0600_mode" — 20 passed, 1 Windows-only mode assertion deselected
• uv run ruff format --check . — passed
• uv run ruff check . — passed
• targeted mypy, pyright, and bandit checks for the changed runtime/configuration paths — passed

Fixes #1036.
Related to #1037.