fix: reveal mode was destroying chat input text

Reveal mode's text replacement was walking ALL text nodes on the page
including contenteditable elements (the chat input box on Claude.ai,
ChatGPT, etc.), overwriting the user's typed text with garbled
revealed content.

Fixed by adding contenteditable checks to:
- revealInElement() — returns early if element is contenteditable
- unrevealInElement() — same
- highlightMatches() — TreeWalker filter rejects contenteditable nodes
- MutationObserver — skips addedNodes and characterData mutations
  inside contenteditable elements

All four code paths now use parent.closest('[contenteditable="true"]')
to detect and skip chat input areas.

https://claude.ai/code/session_01SWSwDfMVij53bCTNSCLMwn

src/content/content.js

@@ -1318,12 +1318,16 @@
   function revealInElement(el) {
     if (SKIP_REVEAL_TAGS.has(el.tagName)) return;
     if (el.classList?.contains('ss-reveal-badge')) return;
+    // Never touch contenteditable elements (chat input boxes)
+    if (el.isContentEditable) return;
 
     const walker = document.createTreeWalker(el, NodeFilter.SHOW_TEXT, {
       acceptNode(node) {
         const parent = node.parentElement;
         if (parent && SKIP_REVEAL_TAGS.has(parent.tagName)) return NodeFilter.FILTER_REJECT;
         if (parent?.closest?.('.ss-autodetect-warning, .ss-presend-warning, .ss-reveal-badge')) return NodeFilter.FILTER_REJECT;
+        // Skip contenteditable areas (chat input)
+        if (parent?.closest?.('[contenteditable="true"]')) return NodeFilter.FILTER_REJECT;
         return NodeFilter.FILTER_ACCEPT;
       }
     });
@@ -1346,8 +1350,15 @@
 
   function unrevealInElement(el) {
     if (SKIP_REVEAL_TAGS.has(el.tagName)) return;
+    if (el.isContentEditable) return;
 
-    const walker = document.createTreeWalker(el, NodeFilter.SHOW_TEXT);
+    const walker = document.createTreeWalker(el, NodeFilter.SHOW_TEXT, {
+      acceptNode(node) {
+        const parent = node.parentElement;
+        if (parent?.closest?.('[contenteditable="true"]')) return NodeFilter.FILTER_REJECT;
+        return NodeFilter.FILTER_ACCEPT;
+      }
+    });
     let textNode;
     while ((textNode = walker.nextNode())) {
       const original = originalTexts.get(textNode);
@@ -1374,6 +1385,7 @@
         const parent = node.parentElement;
         if (parent && SKIP_REVEAL_TAGS.has(parent.tagName)) return NodeFilter.FILTER_REJECT;
         if (parent?.closest?.('.ss-autodetect-warning, .ss-presend-warning, .ss-reveal-badge')) return NodeFilter.FILTER_REJECT;
+        if (parent?.closest?.('[contenteditable="true"]')) return NodeFilter.FILTER_REJECT;
         return NodeFilter.FILTER_ACCEPT;
       }
     });
@@ -1454,10 +1466,16 @@
           // Only do text replacement in reveal mode
           if (settings.revealMode) {
             if (node.nodeType === Node.ELEMENT_NODE) {
-              if (!SKIP_REVEAL_TAGS.has(node.tagName)) {
+              // Skip contenteditable (chat input) and skipped tags
+              if (!SKIP_REVEAL_TAGS.has(node.tagName) &&
+                  !node.isContentEditable &&
+                  !node.closest?.('[contenteditable="true"]')) {
                 revealInElement(node);
               }
             } else if (node.nodeType === Node.TEXT_NODE) {
+              // Skip text nodes inside contenteditable
+              const parent = node.parentElement;
+              if (parent?.closest?.('[contenteditable="true"]')) continue;
               const text = node.textContent;
               if (text && text.length >= MIN_STRING_LENGTH) {
                 if (!originalTexts.has(node)) {
@@ -1479,6 +1497,8 @@
             const text = mutation.target.textContent;
             if (text && text.length >= MIN_STRING_LENGTH) {
               const parent = mutation.target.parentElement;
+              // Skip contenteditable (chat input)
+              if (parent?.closest?.('[contenteditable="true"]')) continue;
               if (parent && !SKIP_REVEAL_TAGS.has(parent.tagName)) {
                 if (!originalTexts.has(mutation.target)) {
                   originalTexts.set(mutation.target, text);