feat: embed admin templates into binary with //go:embed

Move admin templates from templates/admin/*.html to internal/admin/templates/*.html
and embed them using //go:embed directive. This removes the runtime dependency on
having template files on disk, allowing the templates to be compiled into the binary.

Changes:
- Add embed import and //go:embed directive for templates
- Change ParseGlob() to ParseFS() to load from embedded filesystem
- Copy templates to internal/admin/templates/ for embedding

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/internal/admin/server.go b/internal/admin/server.go
index 33413ee..b36c598 100644
--- a/internal/admin/server.go
+++ b/internal/admin/server.go
@@ -4,6 +4,7 @@
 package admin
 
 import (
+	"embed"
 	"fmt"
 	"html/template"
 	"net/http"
@@ -19,6 +20,9 @@ import (
 	"nebbet.no/internal/builder"
 )
 
+//go:embed templates/*.html
+var adminTemplates embed.FS
+
 // Server is an http.Handler that serves the admin post-management UI.
 type Server struct {
 	// PostsDir is the directory where post markdown files are stored,
@@ -353,7 +357,7 @@ func slugify(title string) string {
 	return s
 }
 
-// mustParseTemplates loads admin templates from the templates/admin/ directory.
+// mustParseTemplates loads admin templates from the embedded filesystem.
 func mustParseTemplates() *template.Template {
 	funcs := template.FuncMap{
 		"splitTags": func(s string) []string {
@@ -367,8 +371,8 @@ func mustParseTemplates() *template.Template {
 			return tags
 		},
 	}
-	// Load all .html files from templates/admin/ directory
-	tmpl, err := template.New("admin").Funcs(funcs).ParseGlob("templates/admin/*.html")
+	// Parse templates from embedded filesystem
+	tmpl, err := template.New("admin").Funcs(funcs).ParseFS(adminTemplates, "templates/*.html")
 	if err != nil {
 		panic(fmt.Sprintf("failed to parse admin templates: %v", err))
 	}