Click "Rename" next to the H1 on `/collections/[id]` to open an inline rename form pre-filled with the current name. Save commits the new name and refreshes the page.
## Who can rename
The creator of the collection AND any tenant owner / admin. Same permission posture as renameDocument — restricting writes matches the blast-radius design.
## What stays unchanged
Pinned membership, rule definitions, and ACL grants are unaffected. The rename is a pure metadata edit on the `collections.name` column.
## Audit trail
A `collection.renamed` event lands on the hash-chained audit log on the collection's stream alongside `.created`, `.member-added`, `.member-removed`, `.rule-updated`. The payload carries `{ collectionId, previous, next }`. `/audit?eventType=collection.renamed` answers "who renamed which matter when" without a JOIN.
## Idempotency
Saving the same name (no change) returns without writing an audit event — re-saves don't pollute the chain.