fix(mcp): honor --dry-run for remove (#900)

[ydflow]

Summary

teamai mcp remove --dry-run currently removes managed MCP servers because the global preview flag never reaches the remove handler. Forward it through config loading and the existing MCP reconciler, skip git-exclude cleanup during a preview, and label the output as a dry run.

Type of Change

• Bug fix (non-breaking change that fixes an issue)

Test Plan

• npm run build
• npm run typecheck
• npm run lint
• npx vitest run src/__tests__/mcp-cmd.test.ts — 11 passed
• npx vitest run --config vitest.e2e.config.ts src/__tests__/e2e/mcp-uninstall.test.ts — 1 passed; exercises dist/index.js and verifies MCP config and ownership manifest remain byte-for-byte unchanged after mcp remove --dry-run

The full unit suite was attempted on Windows but did not pass: unrelated tests hit POSIX file-mode expectations, shell differences, file locks, and timeouts. Linux CI is needed for the full-suite result.

Related Issues

Refs #900 (mcp remove row).

Notes for Reviewers

The underlying MCP reconciler already supported dryRun; this change only connects the command to it and avoids the separate git-exclude cleanup on a preview.

[github-actions]

• [P2 non-blocking] docs/usage-guide.md:1270 documents the new preview workflow, but the agent-facing instructions at skill-data/setup/references/manage-admin.md:34 still omit mcp remove --dry-run. The repository rules require behavior changes to update affected skill-data/; synchronize that command example.

The PR description includes a representative real-CLI E2E verification, so testing documentation is sufficient.

[github-actions]

No findings.

• Previous [P2 non-blocking] documentation issue is resolved: skill-data/setup/references/manage-admin.md:34 now documents teamai mcp remove --dry-run.
• The PR description includes a representative real-CLI E2E verification, so testing documentation is sufficient.