Add configuration files and update project documentation

- Introduced .editorconfig for consistent coding styles across the project.
- Added .golangci.yml for Go linting configuration.
- Updated AGENTS.md to clarify project structure and components.
- Enhanced CONTRIBUTING.md with Makefile usage for common tasks.
- Updated Dockerfiles to use Go 1.24 and improved build instructions.
- Refined README.md and deployment documentation for clarity.
- Added testing documentation in testing.md for backend and frontend tests.
- Introduced Makefile for streamlined development commands and tasks.

frontend-nuxt/assets/css/leaflet-overrides.css

@@ -1,6 +1,6 @@
 /* Map container background from theme (DaisyUI base-200) */
 .leaflet-container {
-  background: hsl(var(--b2));
+  background: var(--color-base-200);
 }
 
 /* Override Leaflet default: show tiles even when leaflet-tile-loaded is not applied