fix(webapp): hide admin Debug-Run button for buffered runs + break SpanRun type cycle

Two coupled changes that must land together:

1. The Debug Run dialog's loader (resources.taskruns.$runParam.debug.ts)
   looks up the run by friendlyId in PG, so it returns 404 for buffered
   runs and the dialog renders the global "404: Page not found" view
   instead of the debug surface. Until the debug loader gains its own
   buffered-aware path, gate the button on the synthetic SpanRun's new
   `isBuffered` flag — set true in the buffer fallback, false on the PG
   path, checked at the AdminDebugRun render site in the spans route.

2. Introducing the `isBuffered` literal would alone trigger the
   long-standing SpanRun circular type alias error: SpanRun is inferred
   from `SpanPresenter.call`'s return, which routes through
   `buildSyntheticSpanRun` on the mollifier-buffered branch — and that
   helper is annotated `Promise<SpanRun>`. The literal narrowing made
   the cycle TS-visible ("Type alias 'Result' circularly references
   itself", surfacing as 7 cascading errors across SpanPresenter and
   the spans route).

   Fix the cycle by grounding SpanRun in the PG-path `getRun` method
   (the canonical source for the shape) so the synthetic helper's
   annotation no longer feeds back into SpanRun's definition. Span
   continues to be derived off `call` because its path through
   `#getSpan` has no synthetic indirection and no cycle.

Squashed because applying step 1 without step 2 leaves the branch
typecheck-broken.

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

Author: d-cs

apps/webapp/app/presenters/v3/SpanPresenter.server.ts

@@ -74,9 +74,21 @@ function extractPromptSpanData(properties: Record<string, unknown>): PromptSpanD
   };
 }
 
+// SpanRun is grounded in the PG-path `getRun` method rather than
+// inferred from `call`'s return type. The buffered branch of `call`
+// routes through `buildSyntheticSpanRun`, and that helper is annotated
+// `Promise<SpanRun>` — if SpanRun were derived from `call` it would
+// close a loop TS no longer tolerates ("Type alias 'Result' circularly
+// references itself"). `getRun` is the canonical source for the shape
+// (the synthetic helper just rebuilds the same shape from a buffer
+// snapshot), and it doesn't recurse, so grounding here breaks the
+// cycle while keeping Span available off `call` (Span's path through
+// `#getSpan` has no synthetic indirection).
+export type SpanRun = NonNullable<
+  Awaited<ReturnType<InstanceType<typeof SpanPresenter>["getRun"]>>
+>;
 type Result = Awaited<ReturnType<SpanPresenter["call"]>>;
 export type Span = NonNullable<NonNullable<Result>["span"]>;
-export type SpanRun = NonNullable<NonNullable<Result>["run"]>;
 type FindRunResult = NonNullable<
   Awaited<ReturnType<InstanceType<typeof SpanPresenter>["findRun"]>>
 >;
@@ -406,6 +418,7 @@ export class SpanPresenter extends BasePresenter {
       traceId: run.traceId,
       spanId: run.spanId,
       isCached: !!linkedRunId,
+      isBuffered: false,
       machinePreset: machine?.name,
       taskEventStore: run.taskEventStore,
       externalTraceId,

apps/webapp/app/routes/resources.orgs.$organizationSlug.projects.$projectParam.env.$envParam.runs.$runParam.spans.$spanParam/route.tsx

@@ -1097,7 +1097,7 @@ function RunBody({
               {run.isCached ? "Jump to original run" : "Focus on run"}
             </LinkButton>
           )}
-          <AdminDebugRun friendlyId={run.friendlyId} />
+          {!run.isBuffered && <AdminDebugRun friendlyId={run.friendlyId} />}
         </div>
         <div className="flex items-center">
           {run.logsDeletedAt === null ? (

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

@@ -177,6 +177,7 @@ export async function buildSyntheticSpanRun(args: {
     traceId: run.traceId ?? "",
     spanId: run.spanId ?? "",
     isCached: false,
+    isBuffered: true,
     machinePreset: narrowMachinePreset(run.machinePreset),
     taskEventStore: "taskEvent",
     externalTraceId: undefined,