fix(adapter): resolve all WHYNOT-WP-0002 drift — designbook-refresh green

Triage the three surfaced divergences the governance-correct way (no stack->React
back-edit, no ir/ hand-edit); make adapt-lit/parity-lit/designbook-refresh now
exit 0:

- PipelineStrip: documented TAG_OVERRIDES in scripts/ir-extract.mjs maps the
  React 'PipelineStrip' to the established tag wn-pipeline (the web-component tag
  is an IR-projection detail, not React-dictated; the component name stays
  faithful). Tag now matches the element; parity tests it (no longer skipped).
- PageHeader.actions: the drift detector now collects each element's named slots
  and treats an IR prop honoured by a same-named slot (<slot name="actions">) as
  satisfied (prop-via-slot, informational) rather than prop-missing.
- Sidebar.current: recorded as an auditable accepted divergence in
  adapters/lit/drift.accepted.json (React monolithic 'current' key vs Lit per-item
  'active' on composable <wn-sidebar-item>) — listed, downgraded to info, not gated.

Rendered surfaces (src/, examples/) untouched — verified zero diff; parity renders
all 10 components green. Adapt/parity outputs idempotent (stable re-run).

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

adapters/lit/parity/_parity.json

@@ -1,6 +1,6 @@
 {
   "stack": "lit",
-  "generatedAt": "2026-06-30T07:15:06.747Z",
+  "generatedAt": "2026-06-30T07:49:18.063Z",
   "components": [
     {
       "name": "Button",
@@ -44,14 +44,18 @@
         "w": 117,
         "h": 37
       },
-      "notes": "coverage (drift, not gated): missing actions"
+      "notes": "ok"
     },
     {
       "name": "PipelineStrip",
-      "contract": "skip",
-      "visual": "skip",
+      "contract": "pass",
+      "visual": "pass",
       "diffRatio": null,
-      "notes": "no <wn-pipeline-strip> element (see adapters/lit/drift/PipelineStrip.md)"
+      "box": {
+        "w": 633,
+        "h": 76
+      },
+      "notes": "ok"
     },
     {
       "name": "Sidebar",
@@ -62,7 +66,7 @@
         "w": 273,
         "h": 592
       },
-      "notes": "coverage (drift, not gated): missing current"
+      "notes": "ok"
     },
     {
       "name": "StageDot",
@@ -113,6 +117,6 @@
     "total": 10,
     "contractFail": 0,
     "visualFail": 0,
-    "skipped": 1
+    "skipped": 0
   }
 }