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

docs/architecture/01-state-and-stores.md

@@ -165,6 +165,20 @@ const active = useSnippetStore(selectActiveSnippet);
 > Rule: if you can compute it, do not store it. Add a new state field only for a
 > value that is _input_ the app receives, not output it derives.
 
+### Editing buffers — the sanctioned duplication, and its sync rule
+
+A text field with debounced auto-save (the metadata panel's Name/Comment, the editor
+buffer) legitimately mirrors a store fact into local component state: the local copy is
+the user's in-progress text, the store holds the saved value. This duplication carries an
+obligation the moment the store fact has **another writer** (publish's content-derived
+renaming, import, any store-side mutation): the component must **adopt** a store change it
+didn't make, or its debounced save will write the stale local copy back — silently undoing
+the other writer. The pattern (see `SnippetLibrary`'s `SnippetMeta`): track the last store
+value seen in a ref; when the store value changes, adopt it into local state **unless the
+user has diverged** (local ≠ previous store value) — in-progress typing always wins.
+Keying the component by entity id handles switching entities; this rule handles the same
+entity changing underneath.
+
 ---
 
 ## 3. Where State Lives: Central vs. Per-Feature Stores