fix(webapp): use internal cuid for synth run-header id

The PG path's `RunPresenter.getRun` sets `id: run.id` (internal cuid).
The synth header was setting `id: run.friendlyId`, causing the admin
debug tooltip on the run detail page to show a `run_xxxx` friendly ID
where the PG-resident view shows a cuid. `SyntheticRun.id` is already
the cuid (via `RunId.fromFriendlyId(entry.runId)`), so use it directly.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: d-cs

apps/webapp/app/v3/mollifier/syntheticRunHeader.server.ts

@@ -32,7 +32,13 @@ export function buildSyntheticRunHeader(args: {
   const isFailed = run.status === "FAILED";
 
   return {
-    id: run.friendlyId,
+    // `id` mirrors RunPresenter.getRun's runData (the PG path), which
+    // is the internal cuid — not the friendlyId. SyntheticRun.id is
+    // already the cuid (RunId.fromFriendlyId(entry.runId) in
+    // readFallback.server.ts) so the admin debug tooltip on the run
+    // detail page shows the same format for buffered + materialised
+    // runs.
+    id: run.id,
     number: 1,
     friendlyId: run.friendlyId,
     traceId: run.traceId ?? "",

apps/webapp/test/mollifierSyntheticRunHeader.test.ts

@@ -89,7 +89,10 @@ describe("buildSyntheticRunHeader", () => {
   it("forwards identity and environment fields from the snapshot", () => {
     const header = buildSyntheticRunHeader({ run: makeSyntheticRun(), environment: ENV });
     expect(header.friendlyId).toBe("run_friendly_1");
-    expect(header.id).toBe("run_friendly_1");
+    // `id` mirrors RunPresenter.getRun (the PG path) which puts the
+    // internal cuid in this field. SyntheticRun.id is the cuid; the
+    // header must surface it (not the friendlyId).
+    expect(header.id).toBe("run_internal_1");
     expect(header.traceId).toBe("trace_1");
     expect(header.spanId).toBe("span_1");
     expect(header.environment).toMatchObject({