feat: add Docker, Drone CI, and k8s deployment manifests

- Dockerfile for Python 3.12 FastAPI app
- Drone CI pipeline to build and push to internal registry
- Kubernetes manifests (Deployment, Service, Secret, Namespace)
- ArgoCD Application for GitOps deployment
- Kustomize base configuration

k8s/base/deployment.yaml

@@ -0,0 +1,56 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: invest-api
+  namespace: invest-api
+  labels:
+    app: invest-api
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: invest-api
+  template:
+    metadata:
+      labels:
+        app: invest-api
+    spec:
+      containers:
+        - name: invest-api
+          image: 192.168.68.11:30500/invest-api:latest
+          imagePullPolicy: Always
+          ports:
+            - containerPort: 8000
+              protocol: TCP
+          env:
+            - name: INVEST_API_HOST
+              value: "0.0.0.0"
+            - name: INVEST_API_PORT
+              value: "8000"
+            - name: INVEST_API_LOG_LEVEL
+              value: "info"
+            - name: INVEST_API_CORS_ORIGINS
+              value: '["*"]'
+          envFrom:
+            - secretRef:
+                name: invest-api-secrets
+                optional: true
+          resources:
+            requests:
+              cpu: 100m
+              memory: 256Mi
+            limits:
+              cpu: 500m
+              memory: 512Mi
+          livenessProbe:
+            httpGet:
+              path: /health
+              port: 8000
+            initialDelaySeconds: 15
+            periodSeconds: 30
+          readinessProbe:
+            httpGet:
+              path: /health
+              port: 8000
+            initialDelaySeconds: 5
+            periodSeconds: 10