Add railiance01 deployment artifacts and fix container image build

Introduce Dockerfile, entrypoint, and k8s/railiance manifests for the
ArgoCD GitOps pilot (ISSUE-WP-0003). Rename the Gitea PyPI build arg to
GITEA_PYPI_INDEX_URL so pip still resolves dependencies from PyPI.

k8s/railiance/deployment.yaml

@@ -0,0 +1,71 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: issue-core
+  namespace: issue-core
+  labels:
+    app.kubernetes.io/name: issue-core
+    app.kubernetes.io/part-of: railiance-gitops
+  annotations:
+    argocd.argoproj.io/sync-wave: "1"  # after the ExternalSecret (wave 0)
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: issue-core
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: issue-core
+        app.kubernetes.io/part-of: railiance-gitops
+    spec:
+      # Image is public-pullable from the Gitea registry (per railiance-forge
+      # docs). Add imagePullSecrets: [{name: gitea-registry}] if it becomes private.
+      containers:
+        - name: issue-core
+          image: gitea.coulomb.social/coulomb/issue-core:0.2.0
+          imagePullPolicy: IfNotPresent
+          ports:
+            - name: http
+              containerPort: 8765
+          env:
+            - name: ISSUE_CORE_API_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: issue-core-runtime
+                  key: ISSUE_CORE_API_KEY
+            - name: GITEA_BACKEND_TOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: issue-core-runtime
+                  key: GITEA_BACKEND_TOKEN
+            - name: BACKENDS_TEMPLATE
+              valueFrom:
+                configMapKeyRef:
+                  name: issue-core-backends
+                  key: backends.json
+          readinessProbe:
+            httpGet:
+              path: /healthz
+              port: http
+            initialDelaySeconds: 5
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: http
+            initialDelaySeconds: 10
+            periodSeconds: 20
+          resources:
+            requests:
+              cpu: 50m
+              memory: 128Mi
+            limits:
+              cpu: 500m
+              memory: 256Mi
+          securityContext:
+            allowPrivilegeEscalation: false
+            readOnlyRootFilesystem: false
+            runAsNonRoot: true
+            capabilities:
+              drop: ["ALL"]