feat(web): guide local Core recovery

[sam2tom]

Summary

• open Dashboard by default and preserve product navigation in the URL hash
• classify local gateway/network failures as an explicit Agent Core backend-not-ready state
• provide copyable Docker recovery commands for an existing local stack
• provide a separate first-time path with the pinned Parsar image, container, daemon, and Web proxy setup guidance

Validation

• root Node tests: 67 passed
• Agents client tests: 214 passed
• Web tests: 562 passed
• focused Playwright recovery flow: passed
• Web TypeScript check: passed
• Web production build: passed
• git diff --check: passed

Boundaries

• Web does not access the Docker socket or execute commands
• Web does not create Core credentials, databases, containers, or daemon profiles
• Core process health remains distinct from authenticated API and execution readiness