feat(devops): improve Docker build caching and add dev workflow targets

- Optimize Dockerfile layer caching with --mount=type=cache for Go modules and npm
- Reorganize Dockerfile layers for better cache hit rates
- Improve .dockerignore organization with categorized comments
- Add Makefile targets: up, down, rebuild-app, restart, ps
- Enhance Makefile help output with categorized sections

.dockerignore

@@ -1,10 +1,25 @@
+# Git
 .git
 .gitignore
+
+# Documentation
 README.md
 *.md
-.env
+.env.example
+.editorconfig
+
+# IDE
 .DS_Store
 .vscode
 .idea
+
+# Build artifacts (don't copy into container)
 tmp/
-logs/
+logs/
+*.log
+
+# Dependencies (install fresh in container)
+node_modules/
+
+# Environment
+.env