fix: replace broken 2-char hash with djb2 for keybind code mapping

The previous hash (charCodeAt(0)*256 + charCodeAt(1)) only used the
first 2 characters of KeyboardEvent.code strings, causing all Key*
codes (KeyA, KeyB, ..., KeyZ) to collide to the same numeric value.
This made Ctrl+D and Ctrl+M appear as identical bindings (false
conflict) and broke keybind matching in the web fallback.

djb2 hashes the full string, producing unique values for all codes.

packages/web/src/components/modals/settingsPanels/KeybindsPanel.tsx

@@ -26,7 +26,12 @@ function keyDisplayName(code: string, key: string): string {
 }
 
 function codeToNumeric(code: string): number {
-  return code.charCodeAt(0) * 256 + (code.charCodeAt(1) || 0);
+  // djb2 hash — produces unique numeric IDs for all KeyboardEvent.code values
+  let hash = 5381;
+  for (let i = 0; i < code.length; i++) {
+    hash = ((hash << 5) + hash + code.charCodeAt(i)) | 0;
+  }
+  return hash >>> 0; // ensure unsigned
 }
 
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