gateway: end-to-end top_k for /recall (RecallRequest → handleRecall → auto-recall, clamp 1..50)

[francialisomlimoeiro]

What it does

Adds an optional, additive top_k override to the gateway /recall API:

• src/gateway/types.ts: RecallRequest.top_k?: number (documented; older gateways ignore it).
• src/gateway/server.ts: numeric validation + clamp 1..50 at the edge; non-numeric falls back to config default.
• src/core/tdai-core.ts / src/core/hooks/auto-recall.ts: topK plumbed to searchMemories, clamped again defensively, overrides recall.maxResults.

Tests

Repo vitest suite: 2 files, 15 passed. Happy to add a dedicated top_k unit test if maintainers want one.

[Maxwell-Code07]

Thanks for your contribution and attention! We will review this PR and get back to you as soon as possible.