docs(release): curate the 0.42.0-alpha.4 note

docs/release/v0.42.0-alpha.4.md

@@ -1,5 +1,48 @@
 # v0.42.0-alpha.4
 
+## Hardening, recipes and starter
+
+The final alpha of the 0.42 line (ADR-0120). No new semantics — the line
+closes with integration proof:
+
+- **Validation recipes, verified in CI**: zod and valibot run inside
+  fixture actions with the 422/303 protocol asserted in three engines —
+  [`docs/integrations/validation.md`](https://github.com/open-element/openelement/blob/main/docs/integrations/validation.md).
+  better-auth and Drizzle recipes ship as doc-level guides, honestly
+  marked unverified until a consumer reproduces them.
+- **Starter**: `create` now ships `/contact`, a request-time route
+  exercising the full loop (`rendering: 'dynamic'` + action +
+  `data-open-enhance`), proven by consumer smoke (local build + Nitro
+  node).
+- **Surface bookkeeping**: `PACKAGE_SURFACE.md` records the 0.42
+  additions as unfrozen with their freeze targets.
+- **Performance baseline for 0.44**: request-time render on the fixture
+  is cold 28.6ms, warm p50 1.58ms / p95 2.97ms
+  (`docs/release/v0.42.0-alpha.4-performance.json`).
+- **Fix (from alpha.3)**: the morph could replace an island whose light
+  DOM carried whitespace-only text around the DSD template, resetting its
+  state; the comparison now ignores whitespace-only text nodes, covered
+  by the survival matrix (42/42 in three engines).
+
+## The 0.42.0 alpha line in one paragraph
+
+alpha.1 gave `renderIntent.mode` semantics (dynamic routes skip
+prerendering, served per request by the generated nitro-mount server;
+pages with actions cannot be prerendered). alpha.2 completed the action
+protocol (fail/422, 303 PRG, named actions, ActionResult, no-JS baseline
+proven). alpha.3 added morph-based continuity (islands survive, preserve
+escape hatch, named regions). alpha.4 hardened the line with recipes, a
+loop-exercising starter, and the 0.44 performance baseline. All of it is
+explicitly unfrozen until the 0.42.0 stable decision (TP-6).
+
+## Verification
+
+- Full release-tier gates green; npm `alpha`/`latest` at `0.42.0-alpha.4`;
+  post-publish consumer and third-party WC smoke; fixture suite 42/42 on
+  Chromium, Firefox and WebKit.
+
+---
+
 AutoFlow3 patch release evidence: `publish-existing-v0.42.0-alpha.4-2026-07-27T10-04-40-740Z`.
 
 - Previous package line: `0.42.0-alpha.3`