Add vision-LLM import pipeline for hex terrain classification

Adds a 3-phase pipeline to populate a HexMap from a source image using
Claude's vision capabilities instead of naive pixel-color matching:

Phase 1 (extract-submaps): crops annotated submap PNGs per hex,
  including center + 6 neighbours with SVG overlay.
Phase 2: Claude classifies submaps in a Code session, writing
  classifications.json — resumable across sessions.
Phase 3 (import-from-json): reads classifications.json into the DB.

Also adds assemble-map.ts to reconstruct a full image from a Leaflet
tile pyramid (used to recover the Aventurien source map from kiepenkerl).

Adds CLAUDE.md documenting the approach, scale constants
(PIXELS_PER_MEILE=8, hexSize=40 = 10 Meilen/Hex), and the
Nord/Mitte/Süd region split for the Aventurien map.

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

package.json

@@ -11,7 +11,10 @@
     "test": "vitest run",
     "test:watch": "vitest",
     "server": "tsx server/index.ts",
-    "pipeline:tiles": "tsx pipeline/generate-tiles.ts"
+    "pipeline:tiles": "tsx pipeline/generate-tiles.ts",
+    "pipeline:assemble": "tsx pipeline/assemble-map.ts",
+    "pipeline:extract":  "tsx pipeline/extract-submaps.ts",
+    "pipeline:import":   "tsx pipeline/import-from-json.ts"
   },
   "devDependencies": {
     "@types/cors": "^2.8.19",
@@ -24,6 +27,7 @@
     "vitest": "^3.0.0"
   },
   "dependencies": {
+    "@anthropic-ai/sdk": "^0.89.0",
     "concurrently": "^9.2.1",
     "cors": "^2.8.6",
     "express": "^5.2.1",