Adds 2 tests to tests/test_app_controller_offloading.py covering the
fix from commit 26e57577:
1. test_offload_entry_payload_tool_call_unwraps_result
- Confirms _on_comms_entry with kind=tool_call produces a [REF:script_NNNN.ps1]
reference in payload['script'] and the offloaded file exists with the
original script content. This is the canonical happy path that exercises
the unwrap ref_result.ok + ref_result.data branch.
2. test_offload_entry_payload_preserves_script_on_log_tool_call_error
- Mocks session_logger.log_tool_call to return Result(errors=[...]) and
asserts that payload['script'] is preserved unchanged AND a debug log
is emitted via caplog. This is the failure-path that exercises the
ref_result.errors branch with logging.debug per Heuristic #19.
Both tests use the existing tmp_session_dir and app_controller fixtures
from test_app_controller_offloading.py. The Result / ErrorInfo / ErrorKind
imports are added to the test file's import block.
Refs: 26e57577 (Task 1.3 fix)
Refs: spec.md FR5
ed