fix(AC-331): print errors to console in non-JSON CLI mode

[jayscambler]

Summary

autoctx run silently exited code 1 when exceptions occurred without --json, producing no stdout or stderr. This made L11/L12 escalation scripts impossible to debug.

Root Cause

Exception handlers only wrote errors in JSON mode:

except Exception as exc:
    if json_output:
        _write_json_stderr(str(exc))
    raise typer.Exit(code=1) from exc  # non-JSON: nothing printed!

Fix

Added else branches to all three run command exception handlers (agent-task, generation runner, resume):

else:
    console.print(f"[red]Error: {exc}[/red]")

Test plan

• 3 tests: error visible in non-JSON, interrupt visible in non-JSON, JSON mode unchanged
• ruff clean, full suite 4389 passed

[linear]

AC-331 Bug: autoctx run exits 1 silently for non-JSON mode when generation fails or all gens skipped