Initial commit: snapshot of spesmilo/electrumx 2.0.0

Unmodified source tree of upstream commit 280cb339aa158e099eb936033eecd15719770651
("Merge pull request #389 from SomberNight/202607_release_2_0",
https://github.com/spesmilo/electrumx, release 2.0.0, 3 July 2026).

All Palladium-specific changes are in the commits that follow.

tests/blocks/pivx_mainnet_1000000.json

@@ -0,0 +1,15 @@
+{
+  "hash": "bb6127b99bf96b150c86ac38fde17c47d6c95b460c462ef45fd5043a44479068",
+  "size": 461,
+  "height": 1000000,
+  "merkleroot": "ecafe8267cbc5e4b6f4aec0978b02f0ba47a19828b0f8780e25685184d61c9e2",
+  "tx": [
+    "290871d1dc1673069a4c3efef424278b377becbff0c776e20972d212daa4a3d4",
+    "e217611a8db9ec5994632e1f66727c53e0ba09c406f6c993c8d52f5474efe620"
+  ],
+  "time": 1516510311,
+  "nonce": 0,
+  "bits": "1a7128a9",
+  "previousblockhash": "795ab132be197a0a173cbe3590660235d906e0011052a10206244e0eae4b5152",
+  "block": "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"
+}