Revert CI workflow to use path filters

- Restore paths filter to only trigger on relevant changes
- botserver/, botui/, botlib/, Cargo.toml, Cargo.lock
- Prevents unnecessary CI runs on unrelated changes

.forgejo/workflows/botserver.yaml

@@ -1,8 +1,15 @@
 name: BotServer CI
 
 on:
-  push:
-    branches: [main]
+push:
+  branches: [main]
+  paths:
+  - "botserver/**"
+  - "botui/**"
+  - "botlib/**"
+  - ".forgejo/workflows/botserver.yaml"
+  - "Cargo.toml"
+  - "Cargo.lock"
 
 jobs:
   build: