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>

docs/ralph-improvement-plan.md

@@ -2,7 +2,7 @@
 
 ## Overview
 
-This plan details improvements to Claudeman's Ralph Loop system based on best practices from the Ralph Claude Code repository (https://github.com/frankbria/ralph-claude-code).
+This plan details improvements to Codeman's Ralph Loop system based on best practices from the Ralph Claude Code repository (https://github.com/frankbria/ralph-claude-code).
 
 ## Key Concepts to Implement
 
@@ -181,7 +181,7 @@ Three states: CLOSED → HALF_OPEN → OPEN
 ### 3.1 Template Library
 - Bug Fix, Feature, Refactoring, Test Coverage, Documentation templates
 - Template selector in wizard
-- Custom templates in `~/.claudeman/templates/`
+- Custom templates in `~/.codeman/templates/`
 
 ### 3.2 Tool Permissions
 - Configure allowed Claude tools per loop