fix: Remove fake HAPPY_CODER_API_KEY, use actual Happy Coder env vars

Happy Coder does not require an API key. It uses these environment variables:
- HAPPY_SERVER_URL (optional custom server)
- HAPPY_WEBAPP_URL (optional custom webapp)
- HAPPY_HOME_DIR (data directory)
- HAPPY_EXPERIMENTAL (enable experimental features)

Changes:
- Remove HAPPY_CODER_API_KEY from all files
- Add proper Happy Coder environment variables to StatefulSet
- Add Happy Coder config options to ConfigMap
- Update README with correct Happy Coder configuration
- Update Makefile and docker-compose examples
- Update secrets-example.yaml

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

k8s/configmap.yaml

@@ -7,3 +7,7 @@ data:
   # GitHub repository to clone on startup
   # Example: "https://github.com/username/repository"
   github-repo: ""
+
+  # Happy Coder configuration (optional)
+  # happy-server-url: "https://api.cluster-fluster.com"
+  # happy-webapp-url: "https://app.happy.engineering"

k8s/kustomization.yaml

@@ -14,7 +14,6 @@ resources:
 #   - name: antigravity-secrets
 #     literals:
 #       - github-token=ghp_your_token
-#       - happy-coder-api-key=your_key
 #       - vnc-password=your_password
 
 commonLabels:

k8s/secrets-example.yaml

@@ -11,8 +11,5 @@ stringData:
   # GitHub Personal Access Token (for private repos)
   github-token: "ghp_your_token_here"
 
-  # Happy Coder API Key
-  happy-coder-api-key: "your_happy_coder_api_key"
-
   # VNC Password (optional, for secure VNC access)
   vnc-password: "your_vnc_password"

k8s/statefulset.yaml

@@ -77,13 +77,23 @@ spec:
               name: antigravity
               key: github-token
               optional: true
-        # Happy Coder configuration
-        - name: HAPPY_CODER_API_KEY
+        # Happy Coder configuration (optional)
+        - name: HAPPY_SERVER_URL
           valueFrom:
-            secretKeyRef:
+            configMapKeyRef:
               name: antigravity
-              key: happy-coder-api-key
+              key: happy-server-url
               optional: true
+        - name: HAPPY_WEBAPP_URL
+          valueFrom:
+            configMapKeyRef:
+              name: antigravity
+              key: happy-webapp-url
+              optional: true
+        - name: HAPPY_HOME_DIR
+          value: "/home/claude/.happy"
+        - name: HAPPY_EXPERIMENTAL
+          value: "true"
         resources:
           requests:
             memory: "2Gi"