Find files matching a query. Uses hybrid ranking (semantic + lexical) by default so paraphrased queries still find the right file; pass `mode: "lexical"` for substring-only or `mode: "vector"` for pure semantic similarity. Best for fuzzy concept questions ("anything about my dog?") rather than structural lookups by date or filename — use `list_files` for those. Returns paths, line numbers, and short excerpts. Treat results as discovery and follow up with `read` on the top files for full context.
