pack: economy MVP -- Numismatics + Patchouli + welcome flow, bump to 0.18.0

Adds the currency layer and the first-join experience.

Mods:
- Create: Numismatics 1.0.20  (currency, vendor blocks, piggy banks)
- Patchouli 1.21.1-93         (kept in pack for future rich manual book)

KubeJS scripts (server_scripts/):
- economy_policy.js  remove ALL Waystones recipes; remove coin recipes
                     only (piggy banks etc. stay craftable for now)
- welcome.js         first-login grant: 1 waystone + vanilla written-book
                     "Brass & Sigil Manual v1" (5 pages: welcome,
                     waystones, money, spawn plots, rules). Per-player
                     flag bnsWelcomeGranted in persistentData gates it.

KubeJS scripts (client_scripts/):
- jei_hides.js       hide all Waystones items + 4 coin denominations from
                     the JEI ingredient list. Combined with the recipe
                     removal players never encounter these items via
                     normal play -- only via the welcome grant or the
                     bank exchange.

The written-book manual is the MVP placeholder. When more content lands
(plot system, dynamic exchange, etc.) it'll be replaced by a proper
Patchouli book authored as a tweak jar -- Patchouli's already in the
lockfile so no mod-add will be needed at that point.

pack/overrides/kubejs/client_scripts/jei_hides.js

@@ -0,0 +1,52 @@
+// Brass & Sigil — JEI hides
+//
+// Hides all Waystones items + all Numismatics coin items from the JEI
+// item list. Combined with the server-side recipe removal in
+// economy_policy.js, players don't see crafting recipes OR the item
+// icons in the JEI ingredient list -- they only ever encounter these
+// items through the welcome grant or the bank exchange.
+
+const COLORS = [
+    'white', 'orange', 'magenta', 'light_blue', 'yellow', 'lime',
+    'pink', 'gray', 'light_gray', 'cyan', 'purple', 'blue',
+    'brown', 'green', 'red', 'black',
+];
+
+const WAYSTONE_ITEMS = [
+    // regular waystone variants
+    'waystones:waystone',
+    'waystones:mossy_waystone',
+    'waystones:sandy_waystone',
+    'waystones:blackstone_waystone',
+    'waystones:deepslate_waystone',
+    'waystones:end_stone_waystone',
+    // handheld + plate
+    'waystones:warp_stone',
+    'waystones:warp_scroll',
+    'waystones:bound_scroll',
+    'waystones:return_scroll',
+    'waystones:warp_plate',
+    // sharestones (16 colors) + shards
+    'waystones:sharestone',  // base id if registered
+];
+COLORS.forEach(c => {
+    WAYSTONE_ITEMS.push(`waystones:${c}_sharestone`);
+    WAYSTONE_ITEMS.push(`waystones:${c}_portstone`);
+});
+
+const COIN_ITEMS = [
+    'numismatics:spur',
+    'numismatics:bevel',
+    'numismatics:sundial',
+    'numismatics:sun',
+];
+
+JEIEvents.hideItems(event => {
+    [...WAYSTONE_ITEMS, ...COIN_ITEMS].forEach(id => {
+        try { event.hide(id); } catch (e) {
+            // Some IDs may not exist (e.g. base 'waystones:sharestone' isn't
+            // registered if only colored variants are). Swallow per-item
+            // failures so one bad id doesn't break the whole pass.
+        }
+    });
+});