feat(analytics): replace custom pipeline with Matomo

Removes the hand-rolled analytics endpoint and SQLite event table in favour
of Matomo — a self-hosted, full-featured analytics platform.

k8s:
- Deploy MariaDB 11 + Bitnami Matomo 5 in the solitaire namespace
- Route analytics.aleshym.co ingress to the Matomo service
- Remove Datasette sidecar and its BasicAuth middleware/secret
- Remove the analytics port from the solitaire-server Service

Rust:
- Replace AnalyticsClient (custom HTTP endpoint) with MatomoClient (Matomo
  HTTP Tracking API bulk endpoint); maps game events to Matomo categories
- Add matomo_url + matomo_site_id fields to Settings (serde default → None/1)
- Privacy toggle in Settings now activates when matomo_url is set (not tied
  to SyncBackend::SolitaireServer)
- Remove POST /api/analytics route from solitaire_server

Web:
- Add Matomo JS tracking snippet to game.html (/play page)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

deploy/deployment.yaml

@@ -19,47 +19,6 @@ spec:
       imagePullSecrets:
         - name: gitea-registry
       containers:
-        - name: analytics
-          image: datasetteproject/datasette:0.65.1
-          args:
-            - serve
-            - /data/sol.db
-            - --host
-            - "0.0.0.0"
-            - --port
-            - "8001"
-            - --readonly
-            - --setting
-            - sql_time_limit_ms
-            - "5000"
-            - --setting
-            - max_returned_rows
-            - "1000"
-          ports:
-            - containerPort: 8001
-          volumeMounts:
-            - name: db-data
-              mountPath: /data
-              readOnly: true
-          livenessProbe:
-            httpGet:
-              path: /-/alive
-              port: 8001
-            initialDelaySeconds: 10
-            periodSeconds: 30
-          readinessProbe:
-            httpGet:
-              path: /-/alive
-              port: 8001
-            initialDelaySeconds: 5
-            periodSeconds: 10
-          resources:
-            requests:
-              cpu: 25m
-              memory: 48Mi
-            limits:
-              cpu: 200m
-              memory: 128Mi
         - name: server
           image: solitaire-server
           imagePullPolicy: Always