fix: preserve Codex sessions in isolated runs

[yujiezhang-ops]

Summary

• Add AGENTMEMORY_HOME as the runtime data root for env, preferences, pidfiles, snapshots, and standalone state without changing the user's Codex home.
• Keep clean/new checkout runs able to read ~/.codex/sessions and ~/.codex/archived_sessions while isolating AI-Todo state.
• Add viewer fallbacks for config flags and inbox, and include socksio so LangExtract works behind SOCKS proxies.

Validation

• npx vitest run test/source-scan-codex.test.ts test/env-loader.test.ts test/cli-onboarding.test.ts test/stop-worker-pidfile.test.ts test/viewer-security.test.ts
• LANGEXTRACT_SELF_TEST=1 python3 src/functions/todo-extract-langextract.py
• AGENTMEMORY_TODO_UPDATE_SELF_TEST=1 python3 src/functions/todo-update-llm.py
• node scripts/build-viewer-html.mjs --check
• npm run build
• Clean runtime check with AGENTMEMORY_HOME=/tmp/... and temp iii state: /agentmemory/sessions returned 31 imported Codex sessions; /agentmemory/local-agent-sessions read /Users/ppio/.codex roots; Chrome #sessions showed 62 merged sessions.