feat: cooking assistant can propose creating a recipe

Gives the general chat a createRecipe tool (Vercel AI SDK, stepCountIs(3))
scoped so it can only ever produce a draft — the tool's execute is a pure
echo, no DB write. The route surfaces the tool call as proposedRecipe
alongside the normal text answer; the chat UI renders it as a card with
explicit Create/Discard buttons. Create POSTs to the existing
/api/v1/recipes endpoint — the same code path and tier/recipe-count limit
the manual editor already goes through — so there's exactly one place
that actually creates a recipe row, and nothing happens without the user
clicking Create.

Scoped to the general assistant only (not per-recipe chat), and to one
tool for now — addToShoppingList/generateMealPlan are follow-ups.

v0.45.0

package.json

@@ -1,6 +1,6 @@
 {
   "name": "epicure",
-  "version": "0.44.1",
+  "version": "0.45.0",
   "private": true,
   "scripts": {
     "dev": "pnpm --filter web dev",