Feat v0.2.5 ui polish dead code (#9)

Co-authored-by: Jeffrey Smith <jasafpro@gmail.com>
Co-committed-by: Jeffrey Smith <jasafpro@gmail.com>

server/pages/templates/surfaces/welcome.html

@@ -0,0 +1,25 @@
+{{/*
+    Welcome surface — shown when no extension surfaces are installed.
+    Renders topbar + welcome card with getting-started info.
+*/}}
+
+{{define "surface-welcome"}}
+<div id="welcome-mount" style="display:flex;flex-direction:column;height:100%;"></div>
+{{end}}
+
+{{define "scripts-welcome"}}
+<script type="module" nonce="{{.CSPNonce}}">
+    const { h, render } = await import('{{.BasePath}}/js/sw/vendor/preact.module.js');
+    const hooksModule = await import('{{.BasePath}}/js/sw/vendor/hooks.module.js');
+    const { default: htm } = await import('{{.BasePath}}/js/sw/vendor/htm.module.js');
+    const html = htm.bind(h);
+    window.preact = window.preact || { h, render };
+    window.hooks = window.hooks || hooksModule;
+    window.html = window.html || html;
+
+    const { boot } = await import('{{.BasePath}}/js/sw/sdk/index.js?v={{.Version}}');
+    await boot();
+
+    await import('{{.BasePath}}/js/sw/surfaces/welcome/index.js?v={{.Version}}');
+</script>
+{{end}}