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/adapt.mjs

@@ -20,7 +20,7 @@ import { readFileSync, writeFileSync, existsSync, mkdirSync, readdirSync, rmSync
 import { execSync } from "node:child_process";
 import { join, dirname } from "node:path";
 import { fileURLToPath } from "node:url";
-import { parseLitElements, componentDrift, renderStub } from "./scaffold.mjs";
+import { parseLitElements, componentDrift, renderStub, loadAccepted } from "./scaffold.mjs";
 
 const REPO = join(dirname(fileURLToPath(import.meta.url)), "..", "..");
 const TOKENS_JSON = join(REPO, "ir", "tokens.json");
@@ -130,10 +130,11 @@ function runScaffold() {
     process.exit(2);
   }
   const byTag = parseLitElements(REPO);
+  const accepted = loadAccepted(REPO);
   const contracts = readdirSync(IR_COMPONENTS).filter((f) => f.endsWith(".json"))
     .map((f) => JSON.parse(readFileSync(join(IR_COMPONENTS, f), "utf8")));
 
-  const results = contracts.map((c) => componentDrift(c, byTag))
+  const results = contracts.map((c) => componentDrift(c, byTag, accepted))
     .sort((a, b) => a.name.localeCompare(b.name));
 
   // Per-component drift docs: snapshot, so wipe stale ones first (idempotency rule 4).