Replace the first-run placeholder seed with an onboarding canvas

docs/IMPLEMENTATION-PLAN.md

@@ -94,6 +94,8 @@ preview, and have it survive reload. Single source kind: inline-data specs only
 - `stores/SnippetStore.ts` — `useSnippetStore` with `snippets`, `activeSnippetId`,
   selector-derived `activeSnippet`; load-on-startup; create/select/delete/update actions
   (debounced auto-save of edits, spec §03B). Seed one sample snippet on first run.
+  _(Superseded later: an empty library now shows the onboarding canvas instead of a
+  placeholder seed — spec §02 → First-Run & Empty Workspace.)_
 - `components/SnippetLibrary.tsx` — list + "Create New" pinned item + select/delete.
 - `components/SpecEditor.tsx` — Monaco JSON editor bound to active snippet's spec;
   debounced write-back to the store. (Worker wiring via Vite `?worker` imports —
@@ -111,7 +113,9 @@ preview, and have it survive reload. Single source kind: inline-data specs only
 
 **Manual checks**
 
-- Fresh load seeds a sample snippet that renders a bar chart.
+- Fresh load shows the onboarding canvas (welcome + Create + live example gallery);
+  Create or an example's Add lands you in the editor with a rendered chart. _(M1 originally
+  seeded a sample snippet; replaced by the onboarding canvas — spec §02.)_
 - Type in the editor → preview updates after the debounce; bad JSON → editor keeps
   working, preview shows an error, recovers when fixed.
 - Reload → snippets and selection persist.