Cap maximum limit parameter in Qdrant search

[sre-helmcode]

Context

The RAG MCP server search_knowledge tool accepts a limit parameter passed directly to Qdrant. A large limit value could cause excessive memory usage or slow responses.

Required Change

Add a maximum cap to the limit parameter:

const maxSearchLimit = 20
if limit > maxSearchLimit {
    limit = maxSearchLimit
}

Apply in both:

• cmd/rag-mcp/main.go (MCP server search tool)
• internal/rag/qdrant.go (Qdrant client Search method)

Security Context

Identified during security audit of the RAG feature (MED-3). Prevents abuse via excessively large search requests.

Acceptance Criteria

• Search limit capped at reasonable maximum (e.g., 20)
• Values above the cap are silently reduced
• Default limit remains 5 when not specified