feat(log): add leveled severity and structured context to log wrappers

log.py was bare print-to-stderr wrappers with no levels or attributable
context (issue #252). Add:

- Ordered severities (debug/info/warn/error) gated by
  BOT_BOTTLE_LOG_LEVEL (default info). debug is silent by default;
  error always surfaces (nothing sits above it), so the fatal die path
  stays visible regardless of configured level.
- An optional `context` mapping on every wrapper, rendered as a
  parseable ` [k=v ...]` suffix (keys sorted; whitespace/quoted values
  quoted) so failures can be filtered and correlated.

Default output with no context is byte-identical to the original lines,
so the 100+ existing single-string call sites are unaffected. Wires the
supervise crash path (the example the issue names) to attach error_type
and crash_log context. Adds test_log.py (backward-compat, context
rendering, level gating, die surfacing).

Closes #252.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YcU7nerbg8cVj9R4EkpfLJ

bot_bottle/cli/supervise.py

@@ -292,7 +292,10 @@ def cmd_supervise(argv: list[str]) -> int:
         return e.code if isinstance(e.code, int) else 1
     except Exception as e:  # noqa: W0718 — catch supervise crash for logging
         log_path = _write_crash_log(e)
-        error(f"supervise crashed: {type(e).__name__}: {e}")
+        error(
+            f"supervise crashed: {type(e).__name__}: {e}",
+            context={"error_type": type(e).__name__, "crash_log": str(log_path)},
+        )
         error(f"full traceback written to {log_path}")
         return 1
     return 0