docs(10.1): record D-18/D-19, resolve research questions, add pattern map

Plan checker iteration 1 flagged unresolved research questions and a
missing decision note for golang.org/x/net/html. D-18 approves x/net/html
for the partial sanitizer; D-19 fixes the Discogs widget fill to
[year, format]. STATE marks the phase ready to execute.

.planning/state.json

@@ -51,13 +51,18 @@
     {
       "number": "10",
       "name": "Admin Vue SPA",
-      "status": "pending"
+      "status": "complete"
     },
     {
       "number": "11",
       "name": "Jobs, realtime and search infrastructure",
       "status": "pending"
     },
+    {
+      "number": "11.1",
+      "name": "SummerCMS documentation for humans and AI agents",
+      "status": "pending"
+    },
     {
       "number": "12",
       "name": "Płytarium API — Collections and Albums",
@@ -82,7 +87,7 @@
   "next": {
     "command": "/gsd:progress --next",
     "label": "Advance to the next step",
-    "reason": "Phase 10 of 15 · executing"
+    "reason": "Phase 10.1 of 18 · executing"
   },
-  "updated_at": "2026-09-27T12:11:01.213Z"
+  "updated_at": "2026-09-28T20:34:17.786Z"
 }