refactor(deploy): consolidate install scripts and INSTALL.md into deploy/

- Move scripts/install_mam.sh → deploy/install_mam.sh (local-clone installer)
- Move scripts/generate-env.sh → deploy/generate-env.sh (env helper)
- Move .agents/INSTALL.md → deploy/INSTALL.md (user manual)
- Update install_mam.sh to copy INSTALL.md + generate-env.sh from new paths
- Ship INSTALL.md via deploy/install.sh remote path too (manifest-tracked)
- Update README/BOOTSTRAP generate-env.sh references & repository ASCII layout
- Extend deploy/README.md structure section; extend gitea-ci.yml lint list
- Remove now-empty scripts/ directory
- Fix duplicate ### 2. subsection headers in deploy/README.md (address B-2)
- Correct deploy/INSTALL.md dependency description to match actual checks (address M-1)
- Add local-clone lifecycle caveat (no update.sh/remove.sh) (address M-2)

Closes the deploy consolidation plan and addresses Planner / Reviewer feedback.

deploy/gitea-ci.yml

@@ -33,6 +33,10 @@ jobs:
           shellcheck .agents/skills/multi-agent-mux-stop/scripts/stop_session.sh
           shellcheck .agents/skills/multi-agent-mux-monitor/scripts/reconcile.sh
           shellcheck deploy/install.sh
+          shellcheck deploy/install_mam.sh
+          shellcheck deploy/generate-env.sh
+          shellcheck deploy/update.sh
+          shellcheck deploy/remove.sh
           echo "✅ ShellCheck completed successfully."
 
   lint-python: