Correct README QuickDev, install, update, and verification guidance

[mindcarver]

Outcome

README gives a new user an accurate path from choosing a Thinloop skill through installing, updating, invoking, and verifying Thinloop 0.7.0 across Codex, Claude Code, OpenCode, WorkBuddy, and ZCode.

In scope

• Add a concise QuickDev-first quick start and routing table.
• Distinguish source-linked skill installs from full-plugin installs and prevent duplicate installation guidance.
• Add explicit update/reinstall instructions for each supported local agent.
• Make the macOS/Linux link example safely replace the exact legacy scd-dev-loop link and repair Thinloop-owned links.
• Replace stale or unavailable verification commands with repository-owned commands, real CLI commands, or explicit GUI verification steps.
• Keep version, skill count, hook support, risk gates, and awaiting-uat behavior aligned with v0.7.0.

Out of scope

• Skill behavior changes.
• Manifest or version changes.
• Adding a ZCode CLI that does not exist locally.
• Refactoring historical evaluation artifacts or image asset names.

Acceptance

• README explains the direct QuickDev, Discovery-assisted, and high-risk paths.
• Recommended installation modes are explicit for all five supported agents.
• Upgrade instructions include Claude Code, WorkBuddy, ZCode, Codex, and OpenCode.
• README does not claim repository-local validator scripts or a ZCode CLI that the repository/current local installation does not provide.
• README verification commands exist and pass where executable locally.
• Full repository test suite passes.

Verification

• PR docs: correct QuickDev setup guidance #4 merged into main at 948ffc7490a82d7b43cdf833d77798c8c98c2d57.
• node --test tests/*.test.mjs: 89/89 passed before merge and again on merged main.
• Discovery and Knowledge evaluation case validators: passed.
• Maintenance signal scan: 0 findings.
• Claude Code plugin validation: passed.
• WorkBuddy plugin and marketplace validation: passed.
• POSIX link script: passed in an isolated fixture, including stale-link repair and non-link preservation.
• Codex and OpenCode: seven current source links verified; legacy link absent.
• Claude Code and WorkBuddy: Thinloop 0.7.0 enabled and applications restarted.
• OpenCode runtime: all seven current scd-* skills discovered.
• ZCode Settings: marketplace refreshed; Thinloop 0.7.0 enabled with 7 Skills and 2 Hooks; scd-quickdev present.
• Local and remote main match; worktree is clean.

Current status

awaiting-uat — engineering delivery is complete. The Issue remains open for human real-use acceptance. The repository does not define an awaiting-uat label, so the status is recorded here.

Unknowns

• Windows Junction commands were inspected but not executed because no Windows runtime was available.