feat: port lionroot runtime stack into clean gateway probe

[lionrooter]

Summary

• port the Lionroot runtime patch stack into a clean gateway worktree branch
• include gateway startup timeout handling, plugin overlap handling, iMessage hydration, Zulip lazy-loading, and Lionroot content-routing changes
• make the clean branch suitable as the managed gateway target

Validation

• pnpm exec vitest run src/gateway/server-startup-timeout.test.ts src/imessage/monitor/hydrate-text.test.ts src/imessage/monitor/monitor-provider.attachments.test.ts src/lionroot/routing/content-route.test.ts src/lionroot/routing/content-forward.test.ts src/lionroot/routing/food-image-upload.test.ts src/lionroot/content-intake.test.ts src/plugins/loader.test.ts src/plugins/manifest-registry.test.ts src/agents/system-prompt.test.ts
• pnpm build
• isolated startup smoke on port 18790
• live gateway health after cutover: curl -sf http://127.0.0.1:18789/health

Context

This PR is part of a coordinated OpenClaw runtime normalization/update across proxy, gateway, ClawRouter, and hub docs.

Coordinated PR Set

• openclaw-config: https://github.com/lionrooter/openclaw-config/pull/2
• openclaw-cli-proxy: https://github.com/lionrooter/openclaw-cli-proxy/pull/15
• clawdbot branch repo: feat: port lionroot runtime stack into clean gateway probe #16
• ClawRouter: chore: merge upstream main into lionroot clawrouter ClawRouter#2
• lionroot-openclaw: https://github.com/lionrooter/lionroot-openclaw/pull/53

Suggested Merge Order

1. openclaw-cli-proxy
2. ClawRouter
3. clawdbot branch repo
4. openclaw-config
5. lionroot-openclaw

Note: this change set was republished from lionrooter/openclaw-claude-proxy to lionrooter/openclaw because the original PR targeted an incompatible repo lineage.