Bug: _validate_log_path silently drops subdirectory components in logs.py #2194

Problem

In autobot-backend/api/logs.py, the _validate_log_path function introduced in PR #2101 (#1721) uses Path(file_path).name which extracts only the final filename component, silently dropping any subdirectory:

def _validate_log_path(file_path) -> Path:
    return validate_relative_path(str(Path(file_path).name), LOG_DIR)

For example, Path("/opt/autobot/logs/subdir/app.log").name returns "app.log", so the validated path becomes LOG_DIR/app.log instead of LOG_DIR/subdir/app.log.

Impact

• Requests for nested log files silently resolve to wrong paths (404 or wrong file)
• Behavioral regression from the previous implementation which preserved subdirectory structure
• Severity: medium — current log storage may be flat, but the code is objectively wrong

Fix

Pass the filename directly rather than going through LOG_DIR / filename and stripping back:

def _validate_log_path(filename: str) -> Path:
    return validate_relative_path(filename, LOG_DIR)

Discovered During

Code review of PR #2101 (working on #1721)