[Feature] Failure troubleshooter & smart retry (cjules troubleshoot)

[hahwul]

Provide an interactive command to diagnose failed sessions and recommend corrected retries.

Proposed Command:

cjules troubleshoot <session-id>

Behavior:

• Parse the error logs of a failed session to identify common failures (e.g., crystal compile errors, missing shard dependencies, failing test cases).
• Suggest a remedial --note and ask if the user wants to retry:

  [Diagnostic] Session failed due to:
    -> src/parser.cr:12: undefined method 'foo' for Bar
    
  [Suggestion] Would you like to retry with the following fix note:
    "Fix undefined method 'foo' in src/parser.cr"
  [Y/n]:
  

• If accepted, runs cjules retry <id> --note "..." automatically.