refactor: deduplicate HEX64_REGEX to js/utils/hex.js

Moves the repeatedly defined HEX64_REGEX constant to a shared utility
module to improve maintainability and consistency. Updates all consumers
to import from the new location.

Signed-off-by: Jules <[email protected]>

Co-authored-by: PR0M3TH3AN <[email protected]>

js/dmDecryptor.js

@@ -1,8 +1,9 @@
 // js/dmDecryptor.js
 
 import { normalizeActorKey } from "./nostr/watchHistory.js";
+import { HEX64_REGEX } from "./utils/hex.js";
+
 
-const HEX64_REGEX = /^[0-9a-f]{64}$/;
 
 const SUPPORTED_KINDS = new Set([4, 1059]);