Add client download link and build tarball during deployment

- Added /download/client endpoint to serve the CLI client tarball
- Added "Client" link to navigation in base template
- Created build-client.sh script to clone and package the client
- Updated Dockerfile to run build-client.sh during container build

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

build-client.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+# Build the artdag-client tarball
+# This script is run during deployment to create the downloadable client package
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+CLIENT_REPO="https://git.rose-ash.com/art-dag/client.git"
+TEMP_DIR=$(mktemp -d)
+OUTPUT_FILE="$SCRIPT_DIR/artdag-client.tar.gz"
+
+echo "Building artdag-client.tar.gz..."
+
+# Clone the client repo
+git clone --depth 1 "$CLIENT_REPO" "$TEMP_DIR/artdag-client" 2>/dev/null || {
+    echo "Failed to clone client repo, trying alternative..."
+    # Try GitHub if internal git fails
+    git clone --depth 1 "https://github.com/gilesbradshaw/art-client.git" "$TEMP_DIR/artdag-client" 2>/dev/null || {
+        echo "Error: Could not clone client repository"
+        rm -rf "$TEMP_DIR"
+        exit 1
+    }
+}
+
+# Remove .git directory
+rm -rf "$TEMP_DIR/artdag-client/.git"
+rm -rf "$TEMP_DIR/artdag-client/__pycache__"
+
+# Create tarball
+cd "$TEMP_DIR"
+tar -czf "$OUTPUT_FILE" artdag-client
+
+# Cleanup
+rm -rf "$TEMP_DIR"
+
+echo "Created: $OUTPUT_FILE"
+ls -lh "$OUTPUT_FILE"