Improve search recovery, MCP compatibility, and dependency security

[sajeetharan]

Summary

• add alias-aware, typo-tolerant search with controlled zero-result broadening and clearer profile actions
• add privacy-safe bounded search diagnostics without retaining query text
• reject unsupported MCP protocol versions early with actionable compatibility metadata
• patch production and docs dependency advisories, including a validated Vite override

Validation

• npm test (482 passed)
• npm run build
• npm run docs:build
• npm audit (0 vulnerabilities)
• desktop and mobile browser checks (no horizontal overflow)