ci: use docker build instead of kaniko for ai-assistant

- Use docker:28-cli with docker build/push instead of kaniko
- Fixes 200 OK /blobs/uploads error from registry

.woodpecker.yml

@@ -3,22 +3,20 @@ when:
   event: push
 
 steps:
+  - name: login-registry
+    image: alpine:3.20
+    commands:
+      - echo "${REGISTRY_PASSWORD}" | docker login registry.nxtgauge.com -u "${REGISTRY_USERNAME}" --password-stdin
+
   - name: build-and-push
-    image: woodpeckerci/plugin-kaniko:2.1.1
-    settings:
-      registry: registry.nxtgauge.com
-      repo: nxtgauge-ai-assistant
-      dockerfile: Dockerfile
-      tags:
-        - ${CI_COMMIT_SHA}
-        - latest
-        - high-performance-latest
-      username:
+    image: docker:28-cli
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+    environment:
+      REGISTRY_USERNAME:
         from_secret: REGISTRY_USERNAME
-      password:
+      REGISTRY_PASSWORD:
         from_secret: REGISTRY_PASSWORD
-      insecure: true
-      insecure_pull: true
-      skip_tls_verify: true
-      platforms: linux/amd64
-      cache: false
+    commands:
+      - docker build -t registry.nxtgauge.com/nxtgauge-ai-assistant:latest -f Dockerfile .
+      - docker push registry.nxtgauge.com/nxtgauge-ai-assistant:latest