docs: adapt to Palladium, drop Bitcoin/upstream examples and links

index, features, HOWTO (node requirements, sizes and sync time measured on
Palladium, real startup log, clone URL), environment, peer discovery and
architecture; rpc-interface examples (getinfo, peers, query with real data);
release_process rewritten without tags/PyPI; changelog gets a plm-electrumx
1.0.0 entry above the upstream history. Links point to this repository.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docs/conf.py

@@ -81,9 +81,9 @@ html_theme = 'alabaster'
 # documentation.
 #
 html_theme_options = {
-    'description': 'Lightweight Electrum Server in Python',
-    'github_user': 'spesmilo',
-    'github_repo': 'electrumx',
+    'description': 'Electrum server for Palladium (PLM)',
+    'github_user': 'palladium-coin',
+    'github_repo': 'plm-electrumx',
     'github_button': True,
     'github_type': 'star',
     'github_banner': True,