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/plain-css/_report.json

@@ -1,6 +1,6 @@
 {
   "stack": "plain-css",
-  "generatedAt": "2026-06-30T07:20:50.544Z",
+  "generatedAt": "2026-06-30T07:48:30.643Z",
   "components": [
     {
       "name": "Button",
@@ -48,7 +48,7 @@
       "issues": [
         {
           "kind": "no-counterpart",
-          "detail": "no .wn-pipeline-strip class — stub generated."
+          "detail": "no .wn-pipeline class — stub generated."
         }
       ]
     },

adapters/plain-css/stubs/wn-pipeline.css

@@ -1,3 +1,3 @@
 /* @generated STUB by adapters/plain-css (T10) from ir/components/PipelineStrip.json — write-once. */
 /* PipelineStrip: PipelineStrip — extracted from designbook ui_kits/whynot-control/Chrome.jsx. */
-.wn-pipeline-strip { /* TODO: base appearance per ir/exemplars/PipelineStrip.html */ }
+.wn-pipeline { /* TODO: base appearance per ir/exemplars/PipelineStrip.html */ }