D720 — Indexes, Sources and proposals hold up on a large imported KB

Decision. - A markdown link label may hold one level of square brackets ([Issue — [RFC] x](x.md)). The link graph, index_incomplete and the lint link checks parse it with the same pattern. - A page cited in another page's frontmatter provenance is not orphan: being cited is a way in. - A field whose values are identifiers (every value URL-shaped, or each of at least three carriers holding its own value) is never proposed as a closed vocabulary, neither by missing_value_contract nor by template proposals (#686). - template_proposal makes one proposal per template slug, built from every page that would bind to it across the maps that would declare it. A section or optional field enters only when at least half of those pages, and at least two, carry it. A value list enters only when every map gives the same one. A proposal spanning several maps carries one map_updates entry per map (#687). - index_get with with_hash always returns content. - concept_move adds the plain entry - [title](path) under ## Moved here, with no : moved from suffix. - A source_register duplicate whose locator differs says so (locator_mismatch, existing_locator). - source_list returns cited_by_ids next to the cited_by count.

Why. A KB built by bulk ingest (hundreds of pages, one Source per page) hit each of these at scale. Issue titles with [RFC] became dozens of false "missing" index entries. Every Source cited only in provenance was an orphan. URL fields were proposed as enums. One template slug got six conflicting files. A script reading index_get broke once the index passed 60 KB. A move left 45 suffixes to clean up. Two pages with identical text silently shared one Source. Each case was a rule written for a hand-built KB, and the scale made it visible.

Alternatives rejected. - Escaping brackets when index entries are written: it would not fix pages written by hand or imported, and the parser is the single point every reader goes through. - Deduping Sources by (sha256, locator): two locators with the same content are often the same document (a mirror, a redirect). Reporting the mismatch leaves the choice to the agent. - An index_note option on concept_move: an option nobody would set to keep the suffix. The move is already in the git log. - Per-map template proposals with a conflict warning: a template is one file per KB, so the proposal has to be one too. - Returning an error from index_get over the size guard with with_hash: the caller asked for the content in order to patch it.

Consequences. Every link reader must use the bracket-aware pattern (internal/kb/graph.go, cmd/cartographer/import.go, web/src/lib/linksection.ts, internal/lint): a new copy of the old regex brings the false findings back. The kb-doctor skill applies every map_updates entry of a multi-map proposal. Scoped lint reads every concept's frontmatter once when an orphan candidate appears, which costs one KB walk on that write. identifierValued is the single home of the "this is an identifier" rule.