fix(plugin): add MCP readiness gate and reload-plugins step

[onlycastle]

Summary

• Adds MCP Readiness Gate to bp-setup wizard — retries MCP tool calls (3 attempts with backoff) when the server is still starting after install or /reload-plugins
• Adds explicit /reload-plugins step to README installation guide so users know to reload before first-time setup

Changes

• fix(plugin): add MCP readiness gate to bp-setup wizard
• docs: add reload-plugins step to installation guide

Test Plan

• Install plugin fresh, run bp setup before MCP is ready — verify retry logic and error messages
• Run bp setup after MCP is ready — verify gate passes on first attempt
• Follow README install steps end-to-end — verify /reload-plugins step is clear

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Generated with Claude Code using /ship-it

[onlycastle]

Code Review

Found 5 issues:

1. Step 3 references Step 2 data with no fallback — Step 2 (scan_sessions) is now non-critical, but Step 3 unconditionally says "Display the project list from Step 2". When Step 2 fails, the LLM has no allProjects data to display, leading to undefined behavior in project selection.

2. docs/agent/ not updated for pipeline change — CLAUDE.md requires updating docs/agent/ docs when the pipeline changes. The MCP Readiness Gate is a new pre-phase in bp-setup, but neither PLUGIN.md nor TROUBLESHOOTING.md reflect this.

3. Important Notes contradicts new Step 2 behavior — Line 248 says "Never skip Step 2 — it confirms the plugin works" and line 251 lists only "Steps 4, 5 are non-critical", but the PR makes Step 2 failure non-critical. These lines now contradict the new behavior.

4. README Troubleshooting conflicts with /reload-plugins — The new Quick Start step says to run /reload-plugins after install, but the Troubleshooting table still says "Restart Claude Code after plugin install" for the same MCP-not-starting scenario.

5. Pre-Check "Otherwise" branch is unreachable — Line 45: "Otherwise, call get_user_prefs now" can never fire. The Readiness Gate either succeeds (reuse branch applies) or exits the wizard entirely (step 4). There is no path to Pre-Check without a successful prior call.

Generated with Claude Code

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