chore: rename Claudeman to Codeman

Full product rename across 109 files (~834 occurrences):
- Env vars: CLAUDEMAN_* → CODEMAN_*
- Data dirs: ~/.claudeman/ → ~/.codeman/, ~/claudeman-cases/ → ~/codeman-cases/
- tmux prefix: claudeman- → codeman-
- localStorage: claudeman-* → codeman-*
- Package/CLI: claudeman → codeman
- GitHub repo: Ark0N/Claudeman → Ark0N/Codeman
- systemd service: claudeman-web → codeman-web
- Class: ClaudemanApp → CodemanApp

Migration infrastructure for seamless transition:
- state-store.ts: auto-migrates data directories on startup
- tmux-manager.ts: dual-prefix detection (legacy claudeman- sessions)
- app.js: localStorage key migration (preserves old keys)

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

src/image-watcher.ts

@@ -137,7 +137,7 @@ export class ImageWatcher extends EventEmitter {
   /**
    * Start watching a session's working directory for new images.
    *
-   * @param sessionId - Claudeman session ID
+   * @param sessionId - Codeman session ID
    * @param workingDir - Path to the session's working directory
    */
   watchSession(sessionId: string, workingDir: string): void {
@@ -200,7 +200,7 @@ export class ImageWatcher extends EventEmitter {
   /**
    * Stop watching a session's working directory.
    *
-   * @param sessionId - Claudeman session ID to stop watching
+   * @param sessionId - Codeman session ID to stop watching
    */
   unwatchSession(sessionId: string): void {
     const watcher = this.sessionWatchers.get(sessionId);