ci: Pi-hole DNS, package cache, faster pulls

Route *.zea.lt via LAN Traefik, reuse bun cache under /drone-cache,
and skip redundant image pulls on the Pi runner.

Co-authored-by: Cursor <cursoragent@cursor.com>

.drone.yml

@@ -1,23 +1,39 @@
 kind: pipeline
 type: docker
 name: build-and-push
+
 platform:
   os: linux
   arch: arm64
 
+# Use Pi-hole so *.zea.lt resolves to Traefik on the LAN (not public hairpin)
+dns:
+  - 192.168.0.64
+
+concurrency:
+  limit: 1
+
+clone:
+  depth: 50
+
 steps:
   - name: test
     image: oven/bun:1-alpine
+    pull: false
+    environment:
+      BUN_INSTALL_CACHE_DIR: /drone-cache/bun
     commands:
       - bun install --frozen-lockfile
       - bun run test
 
   - name: build
     image: oven/bun:1-alpine
+    pull: false
     environment:
       # Serialise Angular workers — lower peak RAM, longer build (Pi-friendly)
       NG_BUILD_MAX_WORKERS: "1"
       NODE_OPTIONS: "--max-old-space-size=1536"
+      BUN_INSTALL_CACHE_DIR: /drone-cache/bun
       STRAVA_CLIENT_ID:
         from_secret: strava_client_id
       STRAVA_REDIRECT_URI:
@@ -43,6 +59,7 @@ steps:
 
   - name: docker
     image: plugins/docker
+    pull: false
     settings:
       repo: registry.zea.lt/miczek/tracker
       registry: registry.zea.lt
@@ -51,6 +68,9 @@ steps:
       password:
         from_secret: registry_password
       build_args_from_env: true
+      # Reuse previous image layers when possible
+      cache_from:
+        - registry.zea.lt/miczek/tracker:latest
       tags:
         - latest
         - ${DRONE_COMMIT_SHA:0:7}