Fix PDF decompression, add proper noun detection toggle, bump to 0.9.25

- document-scanner.js: Add missing await on _inflateSync() call — FlateDecode
  streams were not being decompressed because the async function was called
  without await, causing decompressed to hold a Promise instead of data
- content.js, storage.js, options.html, options.js: Gate proper noun / capital
  letter detection behind a new detectProperNouns setting (default off); was
  previously always-on causing noisy false-positive warnings on AI thinking
  output and common capitalized words
- Bump version 0.9.23 → 0.9.25

https://claude.ai/code/session_01ReZUeR1nrYzJeX7fTqwXMw

package.json

@@ -1,6 +1,6 @@
 {
   "name": "silent-send",
-  "version": "0.9.23",
+  "version": "0.9.25",
   "private": true,
   "license": "MIT",
   "description": "Browser extension that substitutes personal data before sending to AI services",