refactor: group scripts into walker/ wikigen/ bundle/

Organize the 16 loose scripts by concern:
  walker/  -- .wbt save tooling (sand, build_wbt, walker_hashes,
              harvest_hashes, recover_key)
  wikigen/ -- MediaWiki page generators (make_*_wiki, render_wiki)
  bundle/  -- Unity/Odin asset extraction (unitybundle, odin_read,
              extract_*, loot_probe, dump_loot_bytes)

The only cross-script imports (build_wbt->walker_hashes,
extract_loot->odin_read) live within the same folder, so each
script's dir on sys.path[0] keeps them resolving with no code
changes. All data paths are absolute, so the moves don't affect
I/O. Named the code dir wikigen/ to avoid colliding with the
generated wiki/ output dir; ignore the regenerable wiki_site/ render.

bundle/extract_loot.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+"""Extract SAND loot/drop tables from the two Odin-binary LootTablesConfig assets.
+
+Decodes conf_worldLootTablesStormConfig + conf_worldLootTablesVoyageConfig (Odin
+SerializedFormat=0 Binary) via odin_read, flattens to a clean dict:
+  { region: { lootTableId: [ {itemBlueprint, countMin, countMax, ...}, ... ] } }
+Writes extracted/loot_tables.json (+ reports any unexpected fields / coverage).
+"""
+import os, sys, json
+import odin_read
+
+EX = "/home/downloadpizza/sand_tools/extracted"
+REGIONS = {
+    "Storm":  "conf_worldLootTablesStormConfig.odin.bin",
+    "Voyage": "conf_worldLootTablesVoyageConfig.odin.bin",
+}
+
+def odin_list(node):
+    """Unwrap an Odin List<T> node -> python list of elements."""
+    if node is None: return []
+    if isinstance(node, list): return node
+    items = node.get("$items", [])
+    # List nodes serialize as one inner array: $items == [[...elements...]]
+    out = []
+    for chunk in items:
+        if isinstance(chunk, list): out.extend(chunk)
+        else: out.append(chunk)
+    return out
+
+def main():
+    result = {}
+    extra_fields = set()
+    item_ids = set()
+    for region, fn in REGIONS.items():
+        path = os.path.join(EX, fn)
+        data = open(path, "rb").read()
+        parsed = odin_read.parse(data)
+        assert parsed["consumed"] == parsed["total"], f"{region}: incomplete parse"
+        tables = odin_list(parsed["roots"]["_lootTables"])
+        region_out = {}
+        for t in tables:
+            tid = t.get("lootTableId")
+            items = odin_list(t.get("items"))
+            rows = []
+            for it in items:
+                row = {k: v for k, v in it.items() if k != "$type"}
+                for k in row:
+                    if k not in ("itemBlueprint", "countMin", "countMax"):
+                        extra_fields.add(k)
+                if "itemBlueprint" in row:
+                    item_ids.add(row["itemBlueprint"])
+                rows.append(row)
+            region_out[tid] = rows
+        result[region] = region_out
+        print(f"{region}: {len(region_out)} loot tables, "
+              f"{sum(len(v) for v in region_out.values())} drop rows")
+    out = os.path.join(EX, "loot_tables.json")
+    json.dump(result, open(out, "w"), indent=1, ensure_ascii=False)
+    print(f"\nwrote {out}")
+    print(f"unique item blueprints referenced: {len(item_ids)}")
+    if extra_fields:
+        print(f"NOTE extra (non count) fields present: {sorted(extra_fields)}")
+    # how many drop-table item ids are NOT in our authoritative item registry?
+    reg_path = os.path.join(EX, "items_registry.json")
+    if os.path.exists(reg_path):
+        reg = set(json.load(open(reg_path))["items"].keys())
+        unknown = sorted(i for i in item_ids if i not in reg)
+        print(f"item blueprints not in items_registry: {len(unknown)}")
+        for u in unknown[:40]:
+            print("   ", u)
+
+if __name__ == "__main__":
+    main()