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>

scripts/codeman-web.service

@@ -0,0 +1,24 @@
+[Unit]
+Description=Codeman Web Server
+After=network.target
+
+[Service]
+Type=simple
+WorkingDirectory=/home/arkon/default/codeman
+ExecStart=/usr/bin/node dist/index.js web --https
+Restart=always
+RestartSec=5
+KillMode=process
+Environment=NODE_ENV=production
+Environment=HOME=/home/arkon
+
+# Logging
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=codeman
+
+# Resource limits
+LimitNOFILE=65536
+
+[Install]
+WantedBy=default.target