refactor!: claim references are claim:TAG

lode is renamed paperclaim. A claim reference is claim:TAG or
claim:host/TAG and a pin claim:TAG@hex6 (claimRef and claimPin in
common.schema.json, spec/18 §18.4, spec/02, spec/20); the eight-character
tags do not change. A project names its claim namespace as
claims.paperclaim, and the main example's targeted receipts take the
scope targeted:paperclaim. No old prefix or name is accepted.

paperspec build regenerated the fixtures and vectors: the claim link's and
the symbol's record IDs, the layer receipt, project.json, the two targeted
receipts and Ben's spot-check, the QA report, the inclusion proof, the log's
checkpoint and tiles, and the signature, spot-check, VRF and checkpoint
vectors. The walkthrough and examples quote the new receipt IDs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SarHTuHhV9cS85XWy2NrLJ

fixtures/records/qa-report.json

@@ -1 +1 @@
-{"at":"2026-10-12T10:00:00Z","by":"ana","delivery":"smithlab evidence pilot (fictional)","docs":["smithlab/hale2026harmonic-damb"],"format":"scienting-qa-report/1","id":"b6dt4h4pv0x98","receipts":["y2zw8ctg5s8dp","gx2s84z9jf9xv"],"reviewers":[{"bound":"0.316340","confidence":"0.95","errors":1,"key":"ana","method":"clopper-pearson","sampled":13}],"signature":{"key":"ana","scheme":"ed25519","value":"7nFBiJ2csiX8Y0lgn3Tp5+7IKlMUMRfVEN3B3pdrgw3rCdEG2VXJaafoJ2lClb19Io2bMpfww3k0epkKfef/Dw=="}}
+{"at":"2026-10-12T10:00:00Z","by":"ana","delivery":"smithlab evidence pilot (fictional)","docs":["smithlab/hale2026harmonic-damb"],"format":"scienting-qa-report/1","id":"whqq47rxzzkp6","receipts":["fhhvg9qrzqp0n","gx2s84z9jf9xv"],"reviewers":[{"bound":"0.316340","confidence":"0.95","errors":1,"key":"ana","method":"clopper-pearson","sampled":13}],"signature":{"key":"ana","scheme":"ed25519","value":"mLB9WGnX0DbRzug2n946waD7c7oWi+MAR4TB1n/ezpeflZBMaP5onaH9vtkm4ztI13rb/Ej04IDIUpBonTq9AA=="}}