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>

package-lock.json

@@ -1,11 +1,11 @@
 {
-  "name": "claudeman",
+  "name": "codeman",
   "version": "0.1619",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
-      "name": "claudeman",
+      "name": "codeman",
       "version": "0.1619",
       "hasInstallScript": true,
       "license": "MIT",
@@ -25,7 +25,7 @@
         "zod": "^4.3.6"
       },
       "bin": {
-        "claudeman": "dist/index.js"
+        "codeman": "dist/index.js"
       },
       "devDependencies": {
         "@types/node": "^20.19.33",