chore: Add size pipeline

.gitea/size.yml

@@ -0,0 +1,19 @@
+buckets:
+  - maxSize: 80
+    label: size/small
+    comment: null
+  - maxSize: 200
+    label: size/medium
+    comment: null
+  - maxSize: 2000
+    label: size/large
+    comment: >
+      👮‍♀️⚠️ This is a friendly reminder that the diff size of this PR is bigger than 
+      200 lines we aim for. Please consider splitting this PR into more digestible pieces!
+  - maxSize: Infinity
+    label: size/huge
+    comment: >
+      👮‍♀️🛑 This PR's diff size is quite huge. 
+      Hopefully you know what you're doing. 
+      If you did not commit a lot of autogenerated files intentionally, 
+      there are few good reasons for this.

.gitea/workflows/size.yml

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+name: Label PRs based on size
+
+on: [pull_request]
+
+jobs:
+  add_pr_size_label:
+    runs-on: ubuntu-latest
+    name: Check PR size
+
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v4
+
+      - name: Label and comment PR
+        uses: boschresearch/pr-size-labeler@v5.0.1
+        with:
+          bucketConfigFile: ".gitea/size.yml"