Caddyfile: fix the /admin/ rewrite (matcher follows the directive)

'@admin rewrite ...' is parsed as a one-liner matcher DEFINITION, so it
re-defined @admin and Caddy rejected the config ('matcher is defined more
than once'), crash-looping the container. Per the Caddyfile matcher docs the
matcher token is the first ARGUMENT after the directive: 'rewrite @admin
/admin.html'. The '*' disambiguator is only needed pre-2.8.0. Validated the
rendered config against the porkbun image: 'Valid configuration'.

dankclaw/Caddyfile

@@ -54,7 +54,7 @@ dankclaw.franksdank.cloud {
 	basicauth @admin {
 		frank REPLACE_WITH_ADMIN_HASH
 	}
-	@admin rewrite * /admin.html
+	rewrite @admin /admin.html
 	root * /srv/homepage
 	file_server
 }

tests/homepage_caddy.bats

@@ -26,5 +26,8 @@ setup() {
 }
 
 @test "the /admin/ path is rewritten to admin.html" {
-    grep -qE "@admin[[:space:]]+rewrite[[:space:]]+\*[[:space:]]+/admin.html" "$CADDY"
+    # The matcher token follows the directive (rewrite @admin ...), per the
+    # Caddyfile matcher docs. A leading '@admin rewrite' is parsed as a
+    # one-liner matcher DEFINITION and re-defines @admin (invalid).
+    grep -qE "rewrite[[:space:]]+@admin[[:space:]]+/admin.html" "$CADDY"
 }