phase 1: scaffold D3/TopoJSON migration structure

- Extract country prison data to assets/data/countries.js (ES module)
- Add ISO numeric→alpha-3 lookup table for TopoJSON ID bridging
- Download world-atlas countries-110m.json (TopoJSON, 108KB)
- Create stub ES modules for map, charts, and UI layers
- Replace ZingChart/jQuery script tags with single ES module entry point
- Preserve original app.js as _app.js.bak for Phase 2+ reference

3 files changed, 10 insertions, 0 deletions

diff --git a/assets/js/map/choropleth.js b/assets/js/map/choropleth.js
new file mode 100644
index 0000000..e7d5d3d
--- /dev/null
+++ b/assets/js/map/choropleth.js
@@ -0,0 +1,4 @@
+// Phase 2: choropleth map rendering, gradient coloring
+export function initMap(container, countries, isoLookup) {}
+export function applyGradient(metricKey) {}
+export function setClickHandler(fn) {}
diff --git a/assets/js/map/tooltip.js b/assets/js/map/tooltip.js
new file mode 100644
index 0000000..c8f112a
--- /dev/null
+++ b/assets/js/map/tooltip.js
@@ -0,0 +1,3 @@
+// Phase 3: hover tooltip
+export function initTooltip() {}
+export function attachTooltip(selection, getContent) {}
diff --git a/assets/js/map/zoom.js b/assets/js/map/zoom.js
new file mode 100644
index 0000000..aec278b
--- /dev/null
+++ b/assets/js/map/zoom.js
@@ -0,0 +1,3 @@
+// Phase 3: zoom and pan behavior
+export function initZoom(svg, mapGroup) {}
+export function resetZoom(svg, zoomBehavior) {}