Snippet naming: content-derived on publish, frozen on explicit rename

docs/architecture/07-naming-and-relationships.md

@@ -464,7 +464,30 @@ user action — there is no separate coordinator module to call.
 
 ---
 
-## 7. Where things live
+## 7. Snippet name provenance — the naming hierarchy
+
+Snippet names (unlike dataset names) need no uniqueness; what they need is a rule for
+**who may rewrite them**. Each snippet carries `nameSource` (spec §09A): `'user'` names
+are frozen — set by an explicit rename (`SnippetStore.renameSnippet`) and never touched
+by the app again; `'auto'` names are app-picked and keep tracking the spec. On publish,
+an auto-named snippet is re-named from the now-published content in priority order: the
+spec's `title` (string, line array, or `{ text }` forms), else a mark + encodings
+description, else the existing name stands. The derivation dialect is deliberately the
+same one `generateChartName` uses for builder output, so manually authored and
+builder-built snippets read alike in the library.
+
+Flow: `core/snippet.ts` (`deriveSnippetName`, `isAutoNamed`, `isDefaultSnippetName`) →
+`SnippetStore.publish` (the only rewrite site) / `renameSnippet` (the freeze site) →
+`SnippetLibrary`'s metadata panel (which must adopt a publish rename — arch 01 §2,
+editing buffers). Records predating `nameSource` have no provenance; `isAutoNamed`
+treats them as user-named unless the name is **provably** app-picked — the timestamp
+default shape, or identical to what `deriveSnippetName` returns for the record's own
+published spec. The conservative default is deliberate: rewriting a chosen name is worse
+than failing to track an auto one.
+
+---
+
+## 8. Where things live
 
 | Concern                                                                  | Location                         | Pure?               | Tested      |
 | ------------------------------------------------------------------------ | -------------------------------- | ------------------- | ----------- |
@@ -474,6 +497,7 @@ user action — there is no separate coordinator module to call.
 | `snippetsReferencingDataset`, `datasetUsageCounts` (reverse-lookup scan) | `src/core/relationships.ts`      | yes                 | unit        |
 | `renameDatasetRefs` → updated count (rename propagation)                 | `src/app/stores/SnippetStore.ts` | no (mutates stores) | integration |
 | `dedupeIncomingNames` (datasets + custom themes)                         | `src/core/import-normalize.ts`   | yes                 | unit        |
+| `deriveSnippetName`, `isAutoNamed` (snippet name provenance)             | `src/core/snippet.ts`            | yes                 | unit        |
 
 The dividing line: anything that takes plain data and returns plain data is
 **core** and unit-tested in isolation; anything that reaches into a Zustand store