feat(registry): add query suggestions and synonym aliases

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Summary

Users search for the same resources with different terms: “Claude Code hook,” “agent skill,” “Cursor rule,” “MCP server,” “context pack,” and similar phrases. Generated query suggestions and synonym aliases would improve API, web, MCP, and Raycast discovery.

Current state

• Search indexes include titles, descriptions, tags, keywords, brand fields, and platforms.
• Query matching is currently literal substring matching.
• There is no generated synonym/alias map or suggestions endpoint/artifact.

Desired behavior

• Generate a deterministic alias/synonym map for common HeyClaude categories, platforms, and workflow terms.
• Add suggestions that clients can show before or during search.
• Feed aliases into ranked search without hiding exact-match behavior.

Implementation notes

• Keep the first version curated and small, sourced from category spec/platform metadata.
• Avoid external search dependencies.
• Consider a /data/search-suggestions.json artifact and optional API route.

Acceptance criteria

• Common synonyms improve search recall without destabilizing exact matches.
• Generated suggestions artifact is deterministic and validated.
• API/MCP/Raycast can consume suggestions later.
• Tests cover alias expansion and suggestion artifact shape.

Validation

• pnpm test:registry-artifacts
• pnpm exec vitest run tests/registry-search-facets.test.ts
• Add or update focused unit tests for the touched API/helper surface.
• Run the narrow relevant validation command for the changed package or route.
• Run git diff --check before opening a PR.