content: document metadata (meta.sx) + Ghost title plumbing + 27 tests (365/365)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/content/scoreboard.json

@@ -4,6 +4,7 @@
     "doc": {"pass": 40, "fail": 0},
     "render": {"pass": 42, "fail": 0},
     "api": {"pass": 26, "fail": 0},
+    "meta": {"pass": 27, "fail": 0},
     "markdown": {"pass": 20, "fail": 0},
     "validate": {"pass": 17, "fail": 0},
     "store": {"pass": 29, "fail": 0},
@@ -14,7 +15,7 @@
     "md-import": {"pass": 24, "fail": 0},
     "fed": {"pass": 20, "fail": 0}
   },
-  "total_pass": 338,
+  "total_pass": 365,
   "total_fail": 0,
-  "total": 338
+  "total": 365
 }