feat: add web-ext tooling for Firefox signing

Add package.json with web-ext dev dependency and npm scripts for
building, linting, signing, and running the Firefox extension.
Signing produces a self-hosted .xpi that persists across restarts
without needing the Mozilla store.

https://claude.ai/code/session_01Dvgwe7XMoSxnWXkih8p1Cw

.env.example

@@ -0,0 +1,8 @@
+# Mozilla Add-on API credentials for Firefox extension signing
+# Get yours at: https://addons.mozilla.org/developers/addon/api/key/
+#
+# Copy this file to .env and fill in your values:
+#   cp .env.example .env
+
+WEB_EXT_API_KEY="user:12345:678"
+WEB_EXT_API_SECRET="your-secret-here"

.gitignore

@@ -3,4 +3,7 @@ node_modules/
 *.crx
 *.pem
 *.zip
+*.xpi
 dist/
+.env
+web-ext-artifacts/

README.md

@@ -28,19 +28,24 @@ A Chrome extension that intercepts personal information and substitutes it with
 5. Click **Load unpacked** → select `dist/chrome/` (or root dir)
 6. Navigate to claude.ai — the extension is active
 
-### Firefox
+### Firefox (signed, persistent)
 1. Clone this repo
-2. Run `./build.sh firefox`
+2. `npm install`
-3. Open `about:debugging` → **This Firefox**
+3. Get your free Mozilla API credentials at https://addons.mozilla.org/developers/addon/api/key/
-4. Click **Load Temporary Add-on** → select `dist/firefox/manifest.json`
+4. `cp .env.example .env` and fill in your key + secret
-5. Navigate to claude.ai — the extension is active
+5. `source .env && npm run sign:firefox`
+6. Install the `.xpi` file from `dist/firefox-signed/` — drag it into Firefox or use File → Open
+7. Navigate to claude.ai — the extension is active
 
-For persistent Firefox installation, package and sign via `web-ext`:
+The signed `.xpi` is permanent — survives restarts, no store listing needed.
-```
-cd dist/firefox && npx web-ext sign --api-key=YOUR_KEY --api-secret=YOUR_SECRET
-```
 
-No store required for either browser in developer mode.
+### Firefox (temporary, for development)
+```
+npm install && npm run run:firefox
+```
+Opens Firefox with the extension pre-loaded. Reloads on file changes.
+
+No store required for either browser.
 
 ## Architecture
 

package.json

@@ -0,0 +1,17 @@
+{
+  "name": "silent-send",
+  "version": "0.1.0",
+  "private": true,
+  "description": "Browser extension that substitutes personal data before sending to AI services",
+  "scripts": {
+    "build:chrome": "./build.sh chrome",
+    "build:firefox": "./build.sh firefox",
+    "build": "./build.sh both",
+    "lint:firefox": "npx web-ext lint --source-dir dist/firefox",
+    "sign:firefox": "./build.sh firefox && npx web-ext sign --source-dir dist/firefox --artifacts-dir dist/firefox-signed --channel unlisted",
+    "run:firefox": "./build.sh firefox && npx web-ext run --source-dir dist/firefox"
+  },
+  "devDependencies": {
+    "web-ext": "^8.4.0"
+  }
+}

web-ext-config.js

@@ -0,0 +1,34 @@
+/**
+ * web-ext configuration for Firefox extension development.
+ *
+ * For signing, you need a Mozilla API key and secret.
+ * Get them at: https://addons.mozilla.org/developers/addon/api/key/
+ *
+ * Set these environment variables before running `npm run sign:firefox`:
+ *   export WEB_EXT_API_KEY="user:12345:678"
+ *   export WEB_EXT_API_SECRET="your-secret-here"
+ *
+ * Or create a .env file (git-ignored) and source it:
+ *   source .env && npm run sign:firefox
+ */
+
+module.exports = {
+  sourceDir: 'dist/firefox',
+  artifactsDir: 'dist/firefox-signed',
+  ignoreFiles: [
+    'generate-icons.html',
+  ],
+  build: {
+    overwriteDest: true,
+  },
+  run: {
+    startUrl: ['https://claude.ai/'],
+    // Firefox Developer Edition or Nightly recommended for MV3
+    // firefox: '/path/to/firefox-developer-edition',
+  },
+  sign: {
+    channel: 'unlisted',
+    // API credentials come from environment variables:
+    //   WEB_EXT_API_KEY and WEB_EXT_API_SECRET
+  },
+};