ci: install Bun via curl (more robust on Forgejo runners)

.forgejo/workflows/ci.yml

@@ -1,7 +1,8 @@
 name: CI
 
 # Vérifie chaque PR (et les push sur dev/main) : typecheck + lint + tests + build.
-# Nécessite un runner Forgejo Actions enregistré (label ubuntu-latest).
+# Nécessite un runner Forgejo Actions enregistré (label ubuntu-latest → image
+# avec git/curl/unzip/node, ex. ghcr.io/catthehacker/ubuntu:act-latest).
 on:
   pull_request:
   push:
@@ -15,9 +16,9 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup Bun
-        uses: oven-sh/setup-bun@v2
-        with:
-          bun-version: 1.3.14
+        run: |
+          curl -fsSL https://bun.sh/install | bash -s "bun-v1.3.14"
+          echo "$HOME/.bun/bin" >> "$GITHUB_PATH"
 
       - name: Install
         run: bun install --frozen-lockfile