feat(story-93): expose server logs to agents via get_server_logs MCP tool

- Add log_buffer module: bounded 1000-line ring buffer with push/get_recent API
- Add slog! macro: drop-in for eprintln! that also captures to ring buffer
- Replace all eprintln! calls across agents, watcher, search, chat, worktree, claude_code with slog!
- Add get_server_logs MCP tool: accepts count (1-500) and optional filter params
- 5 unit tests for log_buffer covering push/retrieve, eviction, filtering, count limits, empty buffer
- 262 tests passing, clippy clean

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/src/io/search.rs

@@ -1,3 +1,4 @@
+use crate::slog;
 use crate::state::SessionState;
 use ignore::WalkBuilder;
 use serde::Serialize;
@@ -52,7 +53,7 @@ pub async fn search_files_impl(query: String, root: PathBuf) -> Result<Vec<Searc
                         });
                     }
                 }
-                Err(err) => eprintln!("Error walking dir: {}", err),
+                Err(err) => slog!("Error walking dir: {}", err),
             }
         }
 

server/src/io/watcher.rs

@@ -15,6 +15,7 @@
 //! via exit-code inspection and silently skips the commit while still broadcasting
 //! the event so connected clients stay in sync.
 
+use crate::slog;
 use notify::{EventKind, RecommendedWatcher, RecursiveMode, Watcher, recommended_watcher};
 use serde::Serialize;
 use std::collections::HashMap;
@@ -151,13 +152,13 @@ fn flush_pending(
         ("remove", item.to_string(), format!("story-kit: remove {item}"))
     };
 
-    eprintln!("[watcher] flush: {commit_msg}");
+    slog!("[watcher] flush: {commit_msg}");
     match git_add_work_and_commit(git_root, &commit_msg) {
         Ok(committed) => {
             if committed {
-                eprintln!("[watcher] committed: {commit_msg}");
+                slog!("[watcher] committed: {commit_msg}");
             } else {
-                eprintln!("[watcher] skipped (already committed): {commit_msg}");
+                slog!("[watcher] skipped (already committed): {commit_msg}");
             }
             let stage = additions.first().map_or("unknown", |(_, s)| s);
             let evt = WatcherEvent {
@@ -169,7 +170,7 @@ fn flush_pending(
             let _ = event_tx.send(evt);
         }
         Err(e) => {
-            eprintln!("[watcher] git error: {e}");
+            slog!("[watcher] git error: {e}");
         }
     }
 }
@@ -192,17 +193,17 @@ pub fn start_watcher(
         }) {
             Ok(w) => w,
             Err(e) => {
-                eprintln!("[watcher] failed to create watcher: {e}");
+                slog!("[watcher] failed to create watcher: {e}");
                 return;
             }
         };
 
         if let Err(e) = watcher.watch(&work_dir, RecursiveMode::Recursive) {
-            eprintln!("[watcher] failed to watch {}: {e}", work_dir.display());
+            slog!("[watcher] failed to watch {}: {e}", work_dir.display());
             return;
         }
 
-        eprintln!("[watcher] watching {}", work_dir.display());
+        slog!("[watcher] watching {}", work_dir.display());
 
         const DEBOUNCE: Duration = Duration::from_millis(300);
 
@@ -237,13 +238,13 @@ pub fn start_watcher(
                     false
                 }
                 Ok(Err(e)) => {
-                    eprintln!("[watcher] notify error: {e}");
+                    slog!("[watcher] notify error: {e}");
                     false
                 }
                 // Debounce window expired — time to flush.
                 Err(mpsc::RecvTimeoutError::Timeout) => true,
                 Err(mpsc::RecvTimeoutError::Disconnected) => {
-                    eprintln!("[watcher] channel disconnected, shutting down");
+                    slog!("[watcher] channel disconnected, shutting down");
                     break;
                 }
             };