feat: Add Pezkuwi chain support with custom signed extensions

- Add PezkuwiAddressConstructor for custom address type handling
- Add custom signed extensions (CheckNonZeroSender, CheckWeight, WeightReclaim, PezkuwiCheckMortality)
- Add pezkuwi.json type definitions
- Update RuntimeSnapshotExt for multiple address type lookups
- Update CHAINS_URL to use GitHub-hosted chains.json with types config
- Add feeViaRuntimeCall support for Pezkuwi chains
- Add debug diagnostics for runtime type issues (to be cleaned before production)
- Add CHANGELOG_PEZKUWI.md documenting all changes

pezkuwi-config/chains.json

@@ -53,10 +53,13 @@
         "typeExtras": null
       }
     ],
-    "types": null,
+    "types": {
+      "overridesCommon": false
+    },
     "additional": {
       "themeColor": "#009639",
-      "defaultBlockTimeMillis": 6000
+      "defaultBlockTimeMillis": 6000,
+      "feeViaRuntimeCall": true
     }
   },
   {
@@ -88,8 +91,12 @@
         "icon": "https://pezkuwichain.io/tokens/HEZ.png"
       }
     ],
+    "types": {
+      "overridesCommon": false
+    },
     "additional": {
-      "themeColor": "#009639"
+      "themeColor": "#009639",
+      "feeViaRuntimeCall": true
     }
   },
   {
@@ -166,10 +173,13 @@
         }
       }
     ],
-    "types": null,
+    "types": {
+      "overridesCommon": false
+    },
     "additional": {
       "themeColor": "#009639",
-      "defaultBlockTimeMillis": 6000
+      "defaultBlockTimeMillis": 6000,
+      "feeViaRuntimeCall": true
     }
   },
   {
@@ -214,10 +224,13 @@
         "typeExtras": null
       }
     ],
-    "types": null,
+    "types": {
+      "overridesCommon": false
+    },
     "additional": {
       "themeColor": "#009639",
-      "defaultBlockTimeMillis": 6000
+      "defaultBlockTimeMillis": 6000,
+      "feeViaRuntimeCall": true
     }
   },
   {