fix(cli): resolve OpenAPI references and validate Linux installs - #190

Summary

• Resolve same-document OpenAPI schema references in operation parameters and JSON request bodies, including nested objects and arrays. Unsupported references remain explicit preparation errors without additional schema downloads.
• Support Arch Linux package installation, removal, and purge through the hosted installer.
• Check vault service readiness after RPM installation in both the hosted and versioned Linux installers. A package-manager success no longer hides vault startup failure.
• Give MCP smoke-test setup a separate bounded deadline so vault reset/reinitialization does not consume the request-response deadline; report the phase when a timeout occurs.

Validation

• pnpm verify passed: 3,596 package tests passed, two skipped; changed-line coverage 97.37%.
• The four macOS reset/logout cases and a controlled 11-second setup regression passed against the built CLI.
• AgentMail's public OpenAPI document successfully prepared the previously failing domain request without invoking the operation.
• Corrected hosted installer installed signed 0.15.0 on Arch x86-64; MCP doctor passed with 55 tools.
• Real Fedora 42 ARM64 tests reproduced the original false-success result. Both corrected installers exit unsuccessfully when namespace restrictions prevent vault startup and succeed when the required isolation is available. MCP doctor passed with 55 tools and vault status responded successfully.
• Shell syntax and whitespace checks passed.

The OpenAPI resolver intentionally leaves external schema references, reference siblings, changed schema scopes, and unresolved cycles unsupported. The installer reports unsupported runtime isolation rather than bypassing it.