Add comprehensive security audit (86 findings across 10 areas)

Secure dev auth with signed tokens, add email support for --user
Simplify breakpoint variables, suppress Sass deprecation warnings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/RSpade/Integrations/Scss/Scss_BundleProcessor.php

@@ -352,6 +352,7 @@ async function compile() {
             sourceMap: enableSourceMaps,
             sourceMapIncludeSources: true,
             verbose: !isProduction,  // Show all deprecation warnings in dev mode
+            silenceDeprecations: ['import'],  // Suppress @import deprecation warnings until Sass 3.0 migration
             loadPaths: [
                 path.dirname(inputFile),
                 basePath + '/rsx',