refactor: remove deprecated native shell installers

- Remove installers/ directory (install.sh, install.ps1, uninstall.sh, uninstall.ps1)
- Update CloudFlare worker to 301 redirect /install* to npm docs
- Remove detectInstallationMethod() - npm is now only install method
- Simplify update-command.ts to npm-only updates
- Clean up tests to remove direct install references

BREAKING CHANGE: Native shell installers (curl/irm) no longer work.
Use `npm install -g @kaitranntt/ccs` instead.

scripts/worker.js

@@ -1,46 +1,26 @@
+/**
+ * CCS CloudFlare Worker - Redirect to npm Installation
+ *
+ * Legacy shell installers are deprecated. This worker now redirects
+ * all /install* and /uninstall* requests to the npm installation docs.
+ */
 export default {
   async fetch(request) {
     const url = new URL(request.url);
+    const docsUrl = 'https://docs.ccs.kaitran.ca/getting-started/installation';
 
-    // Detect platform from User-Agent header
-    const userAgent = request.headers.get('user-agent') || '';
-    const isWindows = userAgent.includes('Windows') || userAgent.includes('Win32');
-    const isPowerShell = userAgent.includes('PowerShell') || userAgent.includes('pwsh');
-
-    // Smart routing with platform detection
-    let filePath;
-    if (url.pathname === '/install' || url.pathname === '/install.sh') {
-      filePath = (isWindows && isPowerShell) ? 'installers/install.ps1' : 'installers/install.sh';
-    } else if (url.pathname === '/install.ps1') {
-      filePath = 'installers/install.ps1';
-    } else if (url.pathname === '/uninstall' || url.pathname === '/uninstall.sh') {
-      filePath = (isWindows && isPowerShell) ? 'installers/uninstall.ps1' : 'installers/uninstall.sh';
-    } else if (url.pathname === '/uninstall.ps1') {
-      filePath = 'installers/uninstall.ps1';
-    } else {
-      return new Response('Not Found', { status: 404 });
+    // Redirect all install/uninstall paths to npm installation docs
+    if (
+      url.pathname === '/install' ||
+      url.pathname === '/install.sh' ||
+      url.pathname === '/install.ps1' ||
+      url.pathname === '/uninstall' ||
+      url.pathname === '/uninstall.sh' ||
+      url.pathname === '/uninstall.ps1'
+    ) {
+      return Response.redirect(docsUrl, 301);
     }
 
-    try {
-      const githubUrl = `https://raw.githubusercontent.com/kaitranntt/ccs/main/${filePath}`;
-      const response = await fetch(githubUrl);
-
-      if (!response.ok) {
-        return new Response('File not found on GitHub', { status: 404 });
-      }
-
-      const contentType = filePath.endsWith('.ps1')
-        ? 'text/plain; charset=utf-8'
-        : 'text/x-shellscript; charset=utf-8';
-
-      return new Response(response.body, {
-        headers: {
-          'Content-Type': contentType,
-          'Cache-Control': 'public, max-age=300'
-        }
-      });
-    } catch (error) {
-      return new Response('Server Error', { status: 500 });
-    }
+    return new Response('Not Found', { status: 404 });
   }
 };