fix(hooks): enable image-read blocking by default for third-party profiles

Match WebSearch hook pattern:
- ENABLED by default for settings/cliproxy profiles
- DISABLED for native Claude accounts (account/default)
- User can override via config: hooks.block_image_read.enabled: false

This ensures CCS CLI users get context protection out-of-the-box
while native Claude subscription users are unaffected.

lib/hooks/block-image-read.cjs

@@ -7,6 +7,11 @@
  *
  * This is a PreToolUse hook that runs BEFORE the tool is executed.
  *
+ * Behavior (matches WebSearch pattern):
+ * - ENABLED by default for third-party profiles (settings, cliproxy)
+ * - DISABLED for native Claude accounts (account, default profiles)
+ * - User can override via config: hooks.block_image_read.enabled: false
+ *
  * Usage:
  *   Configured in ~/.claude/settings.json:
  *   {
@@ -22,10 +27,11 @@
  *     }
  *   }
  *
- * Environment Variables:
- *   CCS_BLOCK_IMAGE_READ=1       - Enable blocking (required)
- *   CCS_BLOCK_IMAGE_READ=0       - Disable blocking (allow all reads)
- *   CCS_DEBUG=1                  - Enable debug output
+ * Environment Variables (set by CCS):
+ *   CCS_BLOCK_IMAGE_READ=1    - Enable blocking (default for third-party)
+ *   CCS_BLOCK_IMAGE_READ=0    - Disable blocking
+ *   CCS_PROFILE_TYPE          - Profile type (account, default, settings, cliproxy)
+ *   CCS_DEBUG=1               - Enable debug output
  *
  * Exit codes:
  *   0 - Allow tool (pass-through)
@@ -53,11 +59,28 @@ process.stdin.on('error', () => {
 });
 
 /**
- * Check if blocking is enabled via environment variable
+ * Check if hook should skip (for native Claude accounts).
+ * Matches WebSearch hook pattern.
  */
-function isBlockingEnabled() {
-  // Must be explicitly enabled
-  return process.env.CCS_BLOCK_IMAGE_READ === '1';
+function shouldSkipHook() {
+  // Account/default profiles use native Claude - don't block
+  const profileType = process.env.CCS_PROFILE_TYPE;
+  if (profileType === 'account' || profileType === 'default') {
+    if (process.env.CCS_DEBUG) {
+      console.error(`[CCS Hook] Skipping image block for profile type: ${profileType}`);
+    }
+    return true;
+  }
+
+  // Explicit disable via config
+  if (process.env.CCS_BLOCK_IMAGE_READ === '0') {
+    if (process.env.CCS_DEBUG) {
+      console.error('[CCS Hook] Image read blocking disabled by config');
+    }
+    return true;
+  }
+
+  return false;
 }
 
 /**
@@ -65,11 +88,8 @@ function isBlockingEnabled() {
  */
 function processHook() {
   try {
-    // Skip if blocking not enabled
-    if (!isBlockingEnabled()) {
-      if (process.env.CCS_DEBUG) {
-        console.error('[CCS Hook] Image read blocking disabled (CCS_BLOCK_IMAGE_READ != 1)');
-      }
+    // Skip for native accounts or explicit disable
+    if (shouldSkipHook()) {
       process.exit(0);
     }