D277 — Asset text is searchable through its owner concept

Decision. search indexes the text of an expanded concept's text assets into the owner's own search document, in a fourth field (assets, body weight 1 in memory and in bm25). A hit is the owner concept; there is no per-asset result. Indexable: a listed text extension, not oversized (D270), valid UTF-8 without NUL, first 256 KiB. Assets are found again by stat signature (path, size, mtime), not by reading them: the SQLite hash of an owner with indexable assets is contentHash + "+" + sha256(signature)[:16], and a concept without them keeps its plain hash.

Why. An asset is dossier evidence (D106), but a value that lived only in one, such as a MAC in an inventory CSV or a flag in a config, was unfindable unless the agent already knew which dossier to open. The owner is the unit of retrieval everywhere else (graph, lint, visibility), so the owner's visibility governs the hit with no new policy.

Alternatives rejected. - Per-asset hits: FTS5 cannot cheaply say which column matched, and every consumer of a hit (concept_read, visibility, graph_context seeding) expects a concept id. - Content hashes of assets on every reconcile: reads every asset on every search; a stat signature reads none. - Extracting PDF/DOCX/images: needs a dependency (docs/conventions.md); the ingestion skill has the agent write their content into the concept. - Indexing assets as their own rows: would make them concepts, which D106 says they are not.

Consequences. The SQLite schema is version 3 (an assets column): the index is rebuilt once on first start after the upgrade. The signature rule is the graph cache's (D241, D245), including the racy window: a signature marked racy is never equal to itself, so the owner is re-read after the window, and the persisted hash never vouches for a racy row. The stat walk lists each concept directory and stats each candidate file, so a no-change reconcile costs a few milliseconds per thousand assets (BenchmarkReconcileNoChangeWithAssets). The SQLite snippet is taken from the assets column only when the body excerpt carries no match mark. A change to the list of indexable extensions changes what search can find without any file changing: reindex with full: true.