feat(matrix): add Sol virtual librarian deployment manifests

Sol is a Matrix bot with E2EE that archives conversations to OpenSearch
and responds via Mistral AI function calling. Adds deployment, PVC,
ConfigMap (sol.toml + system prompt), VaultStaticSecret for credentials,
and production overlay image entry.

base/matrix/sol-deployment.yaml

@@ -0,0 +1,76 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: sol
+  namespace: matrix
+spec:
+  replicas: 1
+  strategy:
+    type: Recreate
+  selector:
+    matchLabels:
+      app: sol
+  template:
+    metadata:
+      labels:
+        app: sol
+    spec:
+      enableServiceLinks: false
+      containers:
+        - name: sol
+          image: sol
+          env:
+            - name: SOL_CONFIG
+              value: /etc/sol/sol.toml
+            - name: SOL_SYSTEM_PROMPT
+              value: /etc/sol/system_prompt.md
+            - name: SOL_MATRIX_ACCESS_TOKEN
+              valueFrom:
+                secretKeyRef:
+                  name: sol-secrets
+                  key: matrix-access-token
+            - name: SOL_MATRIX_DEVICE_ID
+              valueFrom:
+                secretKeyRef:
+                  name: sol-secrets
+                  key: matrix-device-id
+            - name: SOL_MISTRAL_API_KEY
+              valueFrom:
+                secretKeyRef:
+                  name: sol-secrets
+                  key: mistral-api-key
+          volumeMounts:
+            - name: sol-config
+              mountPath: /etc/sol/sol.toml
+              subPath: sol.toml
+              readOnly: true
+            - name: sol-config
+              mountPath: /etc/sol/system_prompt.md
+              subPath: system_prompt.md
+              readOnly: true
+            - name: sol-data
+              mountPath: /data
+          resources:
+            limits:
+              memory: 512Mi
+            requests:
+              memory: 256Mi
+              cpu: 100m
+      volumes:
+        - name: sol-config
+          configMap:
+            name: sol-config
+        - name: sol-data
+          persistentVolumeClaim:
+            claimName: sol-data
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: sol-data
+  namespace: matrix
+spec:
+  accessModes: [ReadWriteOnce]
+  resources:
+    requests:
+      storage: 1Gi