fix: scope correlation-chain query to the exchange's own env

Correlated exchanges always share the env of the one being viewed —
using the globally-selected env from the picker was wrong if the user
switched envs after opening a detail view (or arrived via permalink).

Thread `environment` through:
- `ExecutionStore.ExecutionRecord` gains `environment` field; the
  ClickHouse `executions` table already stores this, just not read back.
- `ClickHouseExecutionStore.findById` SELECT adds the column; mapper
  populates it.
- `ExecutionDetail` gains `environment`; `DetailService` passes through.
- `IngestionService.toExecutionRecord` passes null — this legacy PG
  ingestion path isn't active when ClickHouse is enabled, and the
  read-side is what drives the correlation UI.
- UI `ExchangeHeader` reads `detail.environment ?? storeEnv` and
  extends the TS type locally (schema.d.ts catches up on next regen).

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

ui/src/components/ExecutionDiagram/types.ts

@@ -1,6 +1,9 @@
 import type { components } from '../../api/schema';
 
-export type ExecutionDetail = components['schemas']['ExecutionDetail'];
+export type ExecutionDetail = components['schemas']['ExecutionDetail'] & {
+  /** Environment slug this exchange was recorded in. Added to the backend record; schema.d.ts will pick it up on next openapi regen. */
+  environment?: string;
+};
 export type ProcessorNode = components['schemas']['ProcessorNode'];
 
 export interface NodeExecutionState {