docs: add UI screenshots and maintenance workflow

[vmelikyan]

Reader and task

• Audience: application developers using Lifecycle and future documentation contributors
• Task/outcome: recognize a ready or failed Environment, recover from deployment failures, and give future agents a safe, source-backed docs update workflow

Source of truth

• Lifecycle runtime/schema: 9956d3e70a89c81a23c6502d03e237750c3886a4
• Lifecycle UI behavior and labels: b1df0cd64b4680fb241364be6cab985a2dce1f4f
• Product/runtime verification: exercised healthy and deterministic deploy-failure states in the local system; validated the fixture against the current schema

Documentation changes

• Add a current Lifecycle UI checkpoint to the first-Environment journey
• Replace the deployment-troubleshooting TODO with decision-based Config error, Environment error, Service failure, Console, and redeploy guidance
• Add two reviewed 1440×900 screenshots with neutral identity values, alt text, adjacent instructions, and a maintenance catalog
• Add repo-native AGENTS.md, a thin CLAUDE.md, and the $update-lifecycle-docs skill with source routing, authoring, screenshot, fixture, and cleanup rules
• Require image alt text and iframe titles at the component type boundary
• Add bun run verify to CI and align the contributor README and PR template with the workflow
• Navigation or redirects: rename the existing troubleshooting navigation label; no route changes
• Screenshot fixture/cleanup: temporary authorized private fixture PR closed unmerged; Environment, branch, and worktree removed

Verification

• Skill package validated with the skill-creator validator
• bun run verify (lint, typecheck, 16 tests, 183-page production build)
• Checked changed routes in desktop Chrome at 1440×900
• Checked the currently supported docs theme (src/theme.config.tsx forces dark)
• Confirmed screenshots contain no secrets or personal/private identity data
• Independent source/diff review completed with no remaining blockers

[vmelikyan]

Closing this premature partial PR. The requested deliverable is a consolidated, source-verified gap remediation across both analyses; the workflow and screenshot changes will be resubmitted only as part of appropriately scoped, validated work.