Rebrand for grin.us-ea.st deployment

- Point page metadata, API examples, and README at grin.us-ea.st
- Replace github.com/aglkm/grin-explorer references with
  git.pka.world/butler/grin-explorer (footer link, request UA, README)
- Drop upstream-specific Tor onion link and the grincoin.org donate page
  (route, template, and footer link), since neither applies to this fork

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -1,5 +1,5 @@
-# Grincoin.org (GRIN) Blockchain Explorer
-Blockchain explorer for Grin cryptocurrency.
+# grin.us-ea.st — Grin Blockchain Explorer
+Blockchain explorer for Grin cryptocurrency. Fork of [aglkm/grin-explorer](https://github.com/aglkm/grin-explorer) deployed at [grin.us-ea.st](https://grin.us-ea.st), with branding and example endpoints pointed at our node.
 
 ## What is Grin?
 Grin is the very first, simple and fair MimbleWimble blockchain implementation.
@@ -17,7 +17,7 @@ Grin is the very first, simple and fair MimbleWimble blockchain implementation.
 
 ## Installation
 
-1. Clone repository: `git clone https://github.com/aglkm/grin-explorer.git`
+1. Clone repository: `git clone https://git.pka.world/butler/grin-explorer.git`
 2. Build explorer:
    ```
    cd grin-explorer