fix: reveal mode broken when encryption enabled — encrypted settings blob passed to content script

When at-rest encryption is enabled, storage.onChanged fires with
encrypted blobs for ss_settings. The injector was passing this
encrypted blob directly as settings to the page world content script,
overwriting real settings with { _ssLocalEncrypted: true, data: ... }.

This broke reveal mode, highlights, and any setting toggle because
the content script's settings object became the encrypted blob.

Fix: skip encrypted settings blobs in injector.js (same check already
existed for mappings and identity). The background's settings:updated
message already sends decrypted settings correctly.

https://claude.ai/code/session_01KF4i7Ra7zCEDskxDBaNtcT

manifest.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "Silent Send",
-  "version": "0.9.3",
+  "version": "0.9.4",
   "description": "Intercepts personal info and substitutes it with user-defined replacements before sending to AI services.",
   "permissions": [
     "storage",