feat(licence): contributed manifests are CC0 1.0

Contributed manifests were in no declared condition at all, which left §9a
replication with no grant flowing through it: peers mirror each other's
catalogues wholesale, and every hop of that was unlicensed.

CC0 rather than a share-alike licence, because a share-alike works by asserting
a right in the data and then conditioning its use. The position in
docs/legal-posture.md §3 is that presence timings are facts rather than
protectable expression — asserting copyright in them in order to license them
would contradict that argument in the same repository, and that contradiction is
worth more to an opponent than the licence is worth to us. CC0 also waives the
sui generis database right by name, closing the EU-specific residual exposure
from the contributor's side.

The grant is taken at token issuance, and that is not incidental. There are no
accounts, so there is no sign-up to attach terms to, and a manifest arrives over
POST /manifests with no channel to negotiate over. Acquiring the contribute
capability is the only moment a grant can be made, so POST /tokens now returns
the licence and its terms alongside the token — a licence the server publishes
but never delivers is one no contributor agreed to.

The test pins the scope limit as well as the identifier. Bounding the grant to
the manifest is the half that can fail silently: a reworded term reading onto
the underlying work would purport to grant what no contributor can.

Also records the settled code-licence position across all four repositories in
the legal posture, correcting an earlier claim there that the plugin and
extraction repos declared nothing. Both already carried LICENSE files.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

TRACES: UR-019 | PR-006

docs/requirements.md

@@ -45,6 +45,7 @@ requirement and no fixture-generation step, unlike `scene-actor-extraction`.
 | UR-016 | Accept and store `extraction.gallery_scope`; rank on it (§7) | SR-003 | Medium | Done |
 | UR-017 | Accept per-window belief and identification route; `scenes` are objects | SR-003 | High | Done |
 | UR-018 | Exclude belief and route from `content_id`, replicating them as attributes | SR-003 | High | Done |
+| UR-019 | Contributed manifests are CC0 1.0; the grant is delivered with the token, not merely published | PR-006 | High | Done |
 
 ### Notes on status
 
@@ -133,6 +134,7 @@ topology is the point, so this is a deliberate choice rather than an oversight.
 | UR-012 | T2 | No endpoint accepts embeddings or image data | An `embedding` or `crop` field is an unknown-field `400` |
 | UR-013 | T1 | Stored windows are byte-identical to those submitted | Adjacent windows never merged; a window is never trimmed to a shorter one |
 | UR-014 | T1 | Unknown `jmanifest_version` rejected | Version `2` and version `0` both refused, naming the field |
+| UR-019 | T2 | `POST /tokens` returns the licence and its terms | The terms **bound the grant to the manifest** — a reading that covers the underlying work is the failure, not a missing field |
 | DR-001 | T1 | Unknown field at any nesting depth fails to parse | `movie` and `jellyfin_id` named in the error |
 | DR-003 | T1 | Concurrent writes serialize rather than returning `SQLITE_BUSY` | Failed transaction rolls back fully |
 | DR-005 | T1 | Jobs lease once, reschedule with backoff, survive restart | Stranded lease released at startup; future job not leased early |