Migrate backend from Lovable Cloud to own Supabase (EDU project)

- Point .env + supabase/config.toml at EDU (qgmcpounpkgsjlwosjdi)
- Replace Lovable Google-OAuth shim with native supabase.auth.signInWithOAuth
- Remove src/integrations/lovable and @lovable.dev/cloud-auth-js dependency
- Drop .lovable metadata; gitignore supabase/.temp

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/integrations/lovable/index.ts

@@ -1,38 +0,0 @@
-// This file is auto-generated by Lovable. Do not modify it.
-
-import { createLovableAuth } from "@lovable.dev/cloud-auth-js";
-import { supabase } from "../supabase/client";
-const lovableAuth = createLovableAuth();
-
-type SignInOptions = {
-  redirect_uri?: string;
-  extraParams?: Record<string, string>;
-};
-
-export const lovable = {
-  auth: {
-    signInWithOAuth: async (provider: "google" | "apple" | "microsoft" | "lovable", opts?: SignInOptions) => {
-      const result = await lovableAuth.signInWithOAuth(provider, {
-        redirect_uri: opts?.redirect_uri,
-        extraParams: {
-          ...opts?.extraParams,
-        },
-      });
-
-      if (result.redirected) {
-        return result;
-      }
-
-      if (result.error) {
-        return result;
-      }
-
-      try {
-        await supabase.auth.setSession(result.tokens);
-      } catch (e) {
-        return { error: e instanceof Error ? e : new Error(String(e)) };
-      }
-      return result;
-    },
-  },
-};