Say a local commit publishes nothing (#129)

The local driver sometimes ran `git commit` itself instead of calling
finish_milestone, then told the operator a PR was waiting when none had
been opened. A commit still runs (it's contained, and publishing takes
whatever is there), but when the driver's command commits anywhere in
its line, the harness adds to its result: committed locally only;
nothing is published until finish_milestone, and there is no PR until
then. Structural, at the moment the model would draw the wrong
conclusion (P6), rather than left to it noticing.

Closes #129

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPQ14L3LikyefCMFBqEbKE

nisse-dev/src/nisse_dev/loop/driver.py

@@ -50,6 +50,7 @@ class Screening:
     decision: Literal["run", "refuse", "ask"]
     text: str = ""  # the call's result when not run; for ask, the question
     key: str = ""  # for ask: what an allow would bind to (L3)
+    note: str = ""  # for run: what the harness adds to the call's result
 
 
 class Driver:
@@ -198,6 +199,8 @@ class Driver:
                         break
                     outcome = workspace.dispatch(call.tool, call.arguments)
                     result, ok = outcome.result, outcome.success
+                    if screening.note:
+                        result = f"{result}\n\n[harness] {screening.note}"
                 transcript.append(
                     ToolResult(call_id=call.call_id, result=result, success=ok)
                 )