ci: add Gitea CI workflow and track Convex generated types

- Add .gitea/workflows/ci.yml — runs lint, typecheck, and tests on every push
- Remove convex/_generated from .gitignore and commit the generated files so CI
  has the type information it needs without requiring a live Convex backend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

convex/_generated/api.js

@@ -0,0 +1,23 @@
+/* eslint-disable */
+/**
+ * Generated `api` utility.
+ *
+ * THIS CODE IS AUTOMATICALLY GENERATED.
+ *
+ * To regenerate, run `npx convex dev`.
+ * @module
+ */
+
+import { anyApi, componentsGeneric } from "convex/server";
+
+/**
+ * A utility for referencing Convex functions in your app's API.
+ *
+ * Usage:
+ * ```js
+ * const myFunctionReference = api.myModule.myFunction;
+ * ```
+ */
+export const api = anyApi;
+export const internal = anyApi;
+export const components = componentsGeneric();