hscontrol: consolidate assets into single package

Move favicon.png, style.css, and headscale.svg to hscontrol/assets/
and create a single assets.go file with all embed directives.

Update hscontrol/handlers.go and hscontrol/templates/general.go to
use the centralized assets package.

hscontrol/assets/assets.go

@@ -0,0 +1,24 @@
+// Package assets provides embedded static assets for Headscale.
+// All static files (favicon, CSS, SVG) are embedded here for
+// centralized asset management.
+package assets
+
+import (
+	_ "embed"
+)
+
+// Favicon is the embedded favicon.png file served at /favicon.ico
+//
+//go:embed favicon.png
+var Favicon []byte
+
+// CSS is the embedded style.css stylesheet used in HTML templates.
+// Contains Material for MkDocs design system styles.
+//
+//go:embed style.css
+var CSS string
+
+// SVG is the embedded headscale.svg logo used in HTML templates.
+//
+//go:embed headscale.svg
+var SVG string

hscontrol/assets/style.css

@@ -0,0 +1,147 @@
+/* CSS Variables from Material for MkDocs */
+:root {
+  --md-default-fg-color: rgba(0, 0, 0, 0.87);
+  --md-default-fg-color--light: rgba(0, 0, 0, 0.54);
+  --md-default-fg-color--lighter: rgba(0, 0, 0, 0.32);
+  --md-default-fg-color--lightest: rgba(0, 0, 0, 0.07);
+  --md-code-fg-color: #36464e;
+  --md-code-bg-color: #f5f5f5;
+  --md-primary-fg-color: #4051b5;
+  --md-accent-fg-color: #526cfe;
+  --md-typeset-a-color: var(--md-primary-fg-color);
+  --md-text-font:
+    "Roboto", -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue",
+    Arial, sans-serif;
+  --md-code-font:
+    "Roboto Mono", "SF Mono", Monaco, "Cascadia Code", Consolas, "Courier New",
+    monospace;
+}
+
+/* Base Typography */
+.md-typeset {
+  font-size: 0.8rem;
+  line-height: 1.6;
+  color: var(--md-default-fg-color);
+  font-family: var(--md-text-font);
+  overflow-wrap: break-word;
+  text-align: left;
+}
+
+/* Headings */
+.md-typeset h1 {
+  color: var(--md-default-fg-color--light);
+  font-size: 2em;
+  line-height: 1.3;
+  margin: 0 0 1.25em;
+  font-weight: 300;
+  letter-spacing: -0.01em;
+}
+
+.md-typeset h1:not(:first-child) {
+  margin-top: 2em;
+}
+
+.md-typeset h2 {
+  font-size: 1.5625em;
+  line-height: 1.4;
+  margin: 2.4em 0 0.64em;
+  font-weight: 300;
+  letter-spacing: -0.01em;
+  color: var(--md-default-fg-color--light);
+}
+
+.md-typeset h3 {
+  font-size: 1.25em;
+  line-height: 1.5;
+  margin: 2em 0 0.8em;
+  font-weight: 400;
+  letter-spacing: -0.01em;
+  color: var(--md-default-fg-color--light);
+}
+
+/* Paragraphs and block elements */
+.md-typeset p {
+  margin: 1em 0;
+}
+
+.md-typeset blockquote,
+.md-typeset dl,
+.md-typeset figure,
+.md-typeset ol,
+.md-typeset pre,
+.md-typeset ul {
+  margin-bottom: 1em;
+  margin-top: 1em;
+}
+
+/* Lists */
+.md-typeset ol,
+.md-typeset ul {
+  padding-left: 2em;
+}
+
+/* Links */
+.md-typeset a {
+  color: var(--md-typeset-a-color);
+  text-decoration: none;
+  word-break: break-word;
+}
+
+.md-typeset a:hover,
+.md-typeset a:focus {
+  color: var(--md-accent-fg-color);
+}
+
+/* Code (inline) */
+.md-typeset code {
+  background-color: var(--md-code-bg-color);
+  color: var(--md-code-fg-color);
+  border-radius: 0.1rem;
+  font-size: 0.85em;
+  font-family: var(--md-code-font);
+  padding: 0 0.2941176471em;
+  word-break: break-word;
+}
+
+/* Code blocks (pre) */
+.md-typeset pre {
+  display: block;
+  line-height: 1.4;
+  margin: 1em 0;
+  overflow-x: auto;
+}
+
+.md-typeset pre > code {
+  background-color: var(--md-code-bg-color);
+  color: var(--md-code-fg-color);
+  display: block;
+  padding: 0.7720588235em 1.1764705882em;
+  font-family: var(--md-code-font);
+  font-size: 0.85em;
+  line-height: 1.4;
+  overflow-wrap: break-word;
+  word-wrap: break-word;
+  white-space: pre-wrap;
+}
+
+/* Links in code */
+.md-typeset a code {
+  color: currentcolor;
+}
+
+/* Logo */
+.headscale-logo {
+  display: block;
+  width: 400px;
+  max-width: 100%;
+  height: auto;
+  margin: 0 0 3rem 0;
+  padding: 0;
+}
+
+@media (max-width: 768px) {
+  .headscale-logo {
+    width: 200px;
+    margin-left: 0;
+  }
+}