ci: rewrite Gitea URL to internal for CI npm install

@cal/shared package references gitea.jeffemmett.com which is
unreachable from CI runner. Sed replaces with server:3000.

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

Dockerfile

@@ -6,6 +6,9 @@ WORKDIR /app
 # Copy package files
 COPY package.json package-lock.json* ./
 
+# Replace Gitea public URL with internal for CI builds
+RUN sed -i 's|https://gitea.jeffemmett.com|http://server:3000|g' package.json
+
 # Install dependencies
 RUN npm install