Implement interactive execution plan and strict HTML validation

Features:
- **Interactive Checklist**: 'Review Changes' modal now updates in real-time as save tasks complete.
- **Signal Logging**: Backend emits [SIGNAL] logs for deletions, adoptions, uploads, and reorders.
- **UI Cleanup**: Removed redundant textual 'Execute Progress' log pane.

Build & Quality:
- **HTML Validation**: Added 	ools/validate_html.ts to build pipeline to prevent syntax errors in embedded JS.
- **Strict Build**:
pm run build now runs alidate:html first.

tools/validate_html.ts

@@ -0,0 +1,99 @@
+
+import * as fs from 'fs';
+import * as path from 'path';
+import * as cheerio from 'cheerio';
+import * as ts from 'typescript';
+import { glob } from 'glob';
+
+// Configuration
+const SRC_DIR = 'src';
+
+async function validateHtmlFiles() {
+  console.log(`[HTML Validator] Scanning ${SRC_DIR} for HTML files...`);
+
+  // Find all HTML files
+  const htmlFiles = glob.sync(`${SRC_DIR}/**/*.html`);
+  let hasErrors = false;
+
+  for (const file of htmlFiles) {
+    const absolutPath = path.resolve(file);
+    const content = fs.readFileSync(absolutPath, 'utf-8');
+
+    // Load with source location info enabled
+    // Cast options to any to avoid TS version mismatches with cheerio types
+    const options: any = { sourceCodeLocationInfo: true };
+    const $ = cheerio.load(content, options);
+
+    const scripts = $('script').toArray();
+
+    for (const element of scripts) {
+        // Cast to any to access startIndex safely
+        const node = element as any;
+
+        // Skip external scripts
+        if ($(element).attr('src')) continue;
+
+        const scriptContent = $(element).html();
+        if (!scriptContent) continue;
+
+        // Determine start line of the script tag in the original file
+        // Cheerio (htmlparser2) location info:
+        const loc = node.startIndex !== undefined ?
+            getLineNumber(content, node.startIndex) : 1;
+
+        // Validate Syntax using TypeScript Compiler API
+        const sourceFile = ts.createSourceFile(
+            'virtual.js',
+            scriptContent,
+            ts.ScriptTarget.ES2020,
+            true, // setParentNodes
+            ts.ScriptKind.JS
+        );
+
+        // Cast to any because parseDiagnostics might not be in the public interface depending on version
+        const sf: any = sourceFile;
+
+        if (sf.parseDiagnostics && sf.parseDiagnostics.length > 0) {
+            hasErrors = true;
+            console.error(`\n❌ Syntax Error in ${file}`);
+
+            sf.parseDiagnostics.forEach((diag: any) => {
+                const { line, character } = sourceFile.getLineAndCharacterOfPosition(diag.start!);
+                const message = ts.flattenDiagnosticMessageText(diag.messageText, '\n');
+
+                // Adjust line number: Script Start line + Error line inside script
+                // Note: 'line' is 0-indexed relative to script start
+                const visualLine = loc + line;
+
+                console.error(`   Line ${visualLine}: ${message}`);
+
+                // Show snippet
+                const lines = scriptContent.split('\n');
+                if (lines[line]) {
+                    console.error(`   > ${lines[line].trim()}\n`);
+                }
+            });
+        }
+    }
+  }
+
+  if (hasErrors) {
+    console.error(`\n[HTML Validator] Failed. Syntax errors detected.`);
+    process.exit(1);
+  } else {
+    console.log(`[HTML Validator] Passed. All HTML scripts are valid.`);
+  }
+}
+
+// Helper to calculate line number from char index
+function getLineNumber(fullText: string, index: number): number {
+    return fullText.substring(0, index).split('\n').length;
+}
+
+// Check if run directly
+if (require.main === module) {
+    validateHtmlFiles().catch(err => {
+        console.error("Validator crashed:", err);
+        process.exit(1);
+    });
+}