fix(missions): stop titling commits "phase phase work"

Mission 019fc4e0 pushed "clawmates: phase phase work" — the iteration
marker was interpolated into a slot whose default already said "phase".
A rerun read correctly ("pass 2 phase work"), so only the common case was
wrong. Cosmetic, but it lands in the operator's git history under their
own name now that delivery commits as them.

Subject is now "clawmates: phase work" and "clawmates: phase work
(pass 2)". The test covers both, since the bug lived only in the branch
the previous shape did not exercise.

Co-Authored-By: Claude Opus 5 <[email protected]>

crates/cm-api/src/mission_delivery.rs

@@ -529,7 +529,7 @@ pub async fn commit_phase_work(
             // the author line carries a person's name: without it, autonomous
             // work would be indistinguishable from hand-written commits in
             // `git log`. Keep it on any change to this message.
-            "clawmates: {} phase work\n\
+            "clawmates: phase work{}\n\
              \n\
              Mission: {mission_id}\n\
              Phase: {phase_id}\n\
@@ -537,9 +537,9 @@ pub async fn commit_phase_work(
              Committed by the ClawMates delivery pipeline from the agents' \
              working tree. Authored by agents, not by the named committer.",
             if iteration > 0 {
-                format!("pass {}", iteration + 1)
+                format!(" (pass {})", iteration + 1)
             } else {
-                "phase".to_string()
+                String::new()
             }
         );
         git(repo, &["commit", "--no-verify", "-m", &message]).await?;