last30days v3.0.0

Use last30days when the user wants recent, cross-source evidence from the last 30 days.

The runtime is a single v3 pipeline:

1. plan the query
2. retrieve per (subquery, source)
3. normalize and dedupe
4. extract best snippets
5. fuse with weighted RRF
6. rerank with one relevance score
7. cluster evidence
8. render ranked clusters

Setup: resolve the skill root