Sub-flow exit does not return to parent flow — session gets stuck

[nullhack]

Problem

When a sub-flow reaches an exit (e.g. complete, cancelled), the session stays stuck at that exit. The parent flow never advances to its next state.

Reproduction

1. Define a parent flow with a state that delegates to a sub-flow:

# main-flow.yaml
states:
 - id: architecture
 flow: architecture-flow
 next:
 complete: feature-development # should advance here

2. The sub-flow has exits defined:

# architecture-flow.yaml
exits:
 - complete
states:
 - id: review-signoff
 next:
 approved: complete

3. Transition to the exit:

python -m flowr transition approved --session

4. Session now looks like:

flow: architecture-flow
state: complete
stack: []

5. All subsequent commands fail:

$ python -m flowr check --session
error: State 'complete' not found

$ python -m flowr next --session
error: State 'complete' not found

complete is an exit, not a state, so flowr can't resolve it.

Expected Behavior

When a sub-flow transition targets an exit, flowr should:

1. Resolve the exit against the parent flow's next mapping
2. Update the session to the parent flow + target state
3. Pop the call stack

Workaround

Manually edit .flowr/sessions/<name>.yaml to set flow to the parent flow and state to the correct next state.

Environment

• flowr >= 0.4
• Python 3.13

[nullhack]

Solved in PR #7 (v0.4.0 Refined Semolina, commit c821372) which added flow name resolution, and further in PR #12 (v0.5.0 Fine Sift, commit a7cf199) which added subflow exit resolution with call-stack pop/parent transition lookup. The _resolve_subflow_exit() function in flowr/__main__.py:684 now handles: popping the subflow from the call stack, resolving the exit trigger against the parent flow's next mapping, transitioning the parent session to the target state, and chaining into any subsequent subflow.