spike(92): stop auto-committing intermediate pipeline moves

Filter flush_pending() to only git-commit for terminal stages
(1_upcoming and 6_archived) while still broadcasting WatcherEvents
for all stages so the frontend stays in sync.

Reduces pipeline commits from 5+ to 2 per story run. No system
dependencies on intermediate commits were found.

Preserves merge_failure front matter cleanup from master.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/io/watcher.rs

@@ -155,11 +155,25 @@ fn git_add_work_and_commit(git_root: &Path, message: &str) -> Result<bool, Strin
     Err(format!("git commit failed: {stderr}"))
 }
 
+/// Stages that represent meaningful git checkpoints (creation and archival).
+/// Intermediate stages (current, qa, merge, done) are transient pipeline state
+/// that don't need to be committed — they're only relevant while the server is
+/// running and are broadcast to WebSocket clients for real-time UI updates.
+const COMMIT_WORTHY_STAGES: &[&str] = &["1_upcoming", "6_archived"];
+
+/// Return `true` if changes in `stage` should be committed to git.
+fn should_commit_stage(stage: &str) -> bool {
+    COMMIT_WORTHY_STAGES.contains(&stage)
+}
+
 /// Process a batch of pending (path → stage) entries: commit and broadcast.
 ///
 /// Only files that still exist on disk are used to derive the commit message
 /// (they represent the destination of a move or a new file). Deletions are
 /// captured by `git add -A .story_kit/work/` automatically.
+///
+/// Only terminal stages (`1_upcoming` and `6_archived`) trigger git commits.
+/// All stages broadcast a [`WatcherEvent`] so the frontend stays in sync.
 fn flush_pending(
     pending: &HashMap<PathBuf, String>,
     git_root: &Path,
@@ -200,27 +214,37 @@ fn flush_pending(
         }
     }
 
-    slog!("[watcher] flush: {commit_msg}");
-    match git_add_work_and_commit(git_root, &commit_msg) {
-        Ok(committed) => {
-            if committed {
-                slog!("[watcher] committed: {commit_msg}");
-            } else {
-                slog!("[watcher] skipped (already committed): {commit_msg}");
+    // Only commit for terminal stages; intermediate moves are broadcast-only.
+    let dest_stage = additions.first().map_or("unknown", |(_, s)| *s);
+    let should_commit = should_commit_stage(dest_stage);
+
+    if should_commit {
+        slog!("[watcher] flush: {commit_msg}");
+        match git_add_work_and_commit(git_root, &commit_msg) {
+            Ok(committed) => {
+                if committed {
+                    slog!("[watcher] committed: {commit_msg}");
+                } else {
+                    slog!("[watcher] skipped (already committed): {commit_msg}");
+                }
+            }
+            Err(e) => {
+                slog!("[watcher] git error: {e}");
+                return;
             }
-            let stage = additions.first().map_or("unknown", |(_, s)| s);
-            let evt = WatcherEvent::WorkItem {
-                stage: stage.to_string(),
-                item_id,
-                action: action.to_string(),
-                commit_msg,
-            };
-            let _ = event_tx.send(evt);
-        }
-        Err(e) => {
-            slog!("[watcher] git error: {e}");
         }
+    } else {
+        slog!("[watcher] flush (broadcast-only): {commit_msg}");
     }
+
+    // Always broadcast the event so connected WebSocket clients stay in sync.
+    let evt = WatcherEvent::WorkItem {
+        stage: dest_stage.to_string(),
+        item_id,
+        action: action.to_string(),
+        commit_msg,
+    };
+    let _ = event_tx.send(evt);
 }
 
 /// Scan `work/5_done/` and move any `.md` files whose mtime is older than
@@ -547,7 +571,50 @@ mod tests {
     // ── flush_pending ─────────────────────────────────────────────────────────
 
     #[test]
-    fn flush_pending_commits_and_broadcasts_work_item_for_addition() {
+    fn flush_pending_commits_and_broadcasts_for_terminal_stage() {
+        let tmp = TempDir::new().unwrap();
+        init_git_repo(tmp.path());
+        let stage_dir = make_stage_dir(tmp.path(), "1_upcoming");
+        let story_path = stage_dir.join("42_story_foo.md");
+        fs::write(&story_path, "---\nname: test\n---\n").unwrap();
+
+        let (tx, mut rx) = tokio::sync::broadcast::channel(16);
+        let mut pending = HashMap::new();
+        pending.insert(story_path, "1_upcoming".to_string());
+
+        flush_pending(&pending, tmp.path(), &tx);
+
+        let evt = rx.try_recv().expect("expected a broadcast event");
+        match evt {
+            WatcherEvent::WorkItem {
+                stage,
+                item_id,
+                action,
+                commit_msg,
+            } => {
+                assert_eq!(stage, "1_upcoming");
+                assert_eq!(item_id, "42_story_foo");
+                assert_eq!(action, "create");
+                assert_eq!(commit_msg, "story-kit: create 42_story_foo");
+            }
+            other => panic!("unexpected event: {other:?}"),
+        }
+
+        // Verify the file was actually committed.
+        let log = std::process::Command::new("git")
+            .args(["log", "--oneline", "-1"])
+            .current_dir(tmp.path())
+            .output()
+            .expect("git log");
+        let log_msg = String::from_utf8_lossy(&log.stdout);
+        assert!(
+            log_msg.contains("story-kit: create 42_story_foo"),
+            "terminal stage should produce a git commit"
+        );
+    }
+
+    #[test]
+    fn flush_pending_broadcasts_without_commit_for_intermediate_stage() {
         let tmp = TempDir::new().unwrap();
         init_git_repo(tmp.path());
         let stage_dir = make_stage_dir(tmp.path(), "2_current");
@@ -560,6 +627,7 @@ mod tests {
 
         flush_pending(&pending, tmp.path(), &tx);
 
+        // Event should still be broadcast for frontend sync.
         let evt = rx.try_recv().expect("expected a broadcast event");
         match evt {
             WatcherEvent::WorkItem {
@@ -575,6 +643,18 @@ mod tests {
             }
             other => panic!("unexpected event: {other:?}"),
         }
+
+        // Verify NO git commit was made (only the initial empty commit should exist).
+        let log = std::process::Command::new("git")
+            .args(["log", "--oneline"])
+            .current_dir(tmp.path())
+            .output()
+            .expect("git log");
+        let log_msg = String::from_utf8_lossy(&log.stdout);
+        assert!(
+            !log_msg.contains("story-kit:"),
+            "intermediate stage should NOT produce a git commit"
+        );
     }
 
     #[test]
@@ -600,6 +680,7 @@ mod tests {
 
             flush_pending(&pending, tmp.path(), &tx);
 
+            // All stages should broadcast events regardless of commit behavior.
             let evt = rx.try_recv().expect("expected broadcast for stage {stage}");
             match evt {
                 WatcherEvent::WorkItem {
@@ -853,6 +934,20 @@ mod tests {
         );
     }
 
+    #[test]
+    fn should_commit_stage_only_for_terminal_stages() {
+        // Terminal stages — should commit.
+        assert!(should_commit_stage("1_upcoming"));
+        assert!(should_commit_stage("6_archived"));
+        // Intermediate stages — broadcast-only, no commit.
+        assert!(!should_commit_stage("2_current"));
+        assert!(!should_commit_stage("3_qa"));
+        assert!(!should_commit_stage("4_merge"));
+        assert!(!should_commit_stage("5_done"));
+        // Unknown — no commit.
+        assert!(!should_commit_stage("unknown"));
+    }
+
     #[test]
     fn stage_metadata_returns_correct_actions() {
         let (action, msg) = stage_metadata("2_current", "42_story_foo").unwrap();