Create /var/lib/pixa directory in Docker image for database/cache

- Change default StateDir from ./data to /var/lib/pixa (proper Unix convention)
- Create directory owned by pixad user in Dockerfile
- Set WORKDIR to /var/lib/pixa

Dockerfile

@@ -35,9 +35,13 @@ RUN apk add --no-cache \
 # Copy binary from builder
 COPY --from=builder /pixad /usr/local/bin/pixad
 
-# Create non-root user
-RUN adduser -D -H -s /sbin/nologin pixad
+# Create non-root user and data directory
+RUN adduser -D -H -s /sbin/nologin pixad && \
+    mkdir -p /var/lib/pixa && \
+    chown pixad:pixad /var/lib/pixa
+
 USER pixad
+WORKDIR /var/lib/pixa
 
 EXPOSE 8080
 

internal/config/config.go

@@ -17,7 +17,7 @@ import (
 // Default configuration values.
 const (
 	DefaultPort                       = 8080
-	DefaultStateDir                   = "./data"
+	DefaultStateDir                   = "/var/lib/pixa"
 	DefaultUpstreamConnectionsPerHost = 20
 )