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

spec/02-model.md

@@ -4,7 +4,7 @@
 
 | Object | Is | Identified by |
 | --- | --- | --- |
-| Work | The intellectual work, across all its versions. | A work key ([2.4](#24-work-and-document-keys)), and `same_as` identifiers: `doi:`, `arxiv:`, `isbn:`, `pmid:`, `pmcid:`, `openalex:`, `url:` or `lode:`. |
+| Work | The intellectual work, across all its versions. | A work key ([2.4](#24-work-and-document-keys)), and `same_as` identifiers: `doi:`, `arxiv:`, `isbn:`, `pmid:`, `pmcid:`, `openalex:`, `url:` or `claim:`. |
 | Version | One expression of the work: a preprint, an accepted manuscript, the version of record, an erratum, Supporting Information, a draft. | The work's key and a version type, with an optional sequence number and date. |
 | Witness | One file of a version: a PDF, JATS XML, a LaTeX source archive, an HTML page, an EPUB, a Typst project. | The SHA-256 of its bytes. |
 | Document | The text established for one version from one or more witnesses. | A key, and a root hash per revision. |
@@ -83,8 +83,8 @@ The stop words are `a an the of on in for to and or at by with from as into onto
 
 **The identity** is the work's first identifier among `doi`, `arxiv`, `isbn`, `pmid`, `pmcid` and `openalex` in `same_as`, in that order, written `<kind>:<value>` with a DOI's ASCII letters lower-cased.
 A work with none has the identity `meta:<title words>|<year>|<family>` from the same folded parts.
-`url:` and `lode:` identifiers name copies and claims, not the work, and never enter the identity.
-A `lode:` identifier is a claim reference as a layer writes one, `lode:<tag>` or `lode:<host>/<tag>` ([18.4](18-layers.md#184-bodies)).
+`url:` and `claim:` identifiers name copies and claims, not the work, and never enter the identity.
+A `claim:` identifier is a claim reference as a layer writes one, `claim:<tag>` or `claim:<host>/<tag>` ([18.4](18-layers.md#184-bodies)).
 
 **The hash part** is the leading bits of SHA-256 of `scienting-key/1:` followed by the identity, in UTF-8, written in lowercase Crockford base32, five bits a character: four characters, or, when another work in the store already holds that key, six, eight and so on until the key is free.
 A key is minted once, when the work enters a store, and never recomputed: a corrected title or a year revised later leaves it alone, while the hash of an identifier still shows which work the key names.