blogimport: Q-M4 live source — internal-data query adapter (75/75)

source.sx: live-source adapter resolving Q-M4 (internal-data query, not direct PG).
Injected fetch-fn transport port (hexagonal seam); parse-row maps a blog post-row to
the importer post dict and parses the :lexical JSON string via dream-json-parse.
End-to-end drivers: backfill! (enumerate->fetch->import) and sync-verify
(enumerate->fetch->verify), + backfill-ids! explicit-id fallback.

Tests mock the transport against the documented response contract incl. a real lexical
JSON string. README flags the one blog-side gap (add a published-posts enumeration
query) + production fetch_data wiring (lives in lib/host). source 20/20; total 75/75.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/blogimport/scoreboard.json

@@ -2,9 +2,10 @@
   "suites": {
     "lexical": {"pass": 23, "fail": 0},
     "import": {"pass": 21, "fail": 0},
-    "verify": {"pass": 11, "fail": 0}
+    "verify": {"pass": 11, "fail": 0},
+    "source": {"pass": 20, "fail": 0}
   },
-  "total_pass": 55,
+  "total_pass": 75,
   "total_fail": 0,
-  "total": 55
+  "total": 75
 }