chore(server-changes): tighten env-not-found-404 entry to a single line

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

Author: d-cs

.server-changes/env-not-found-404.md

@@ -3,4 +3,4 @@ area: webapp
 type: fix
 ---
 
-Return 404 instead of 500 when a dashboard loader is hit with a slug that no longer exists. Affected loaders (runs, sessions, batches, schedule detail) threw bare `Error("Environment not found")` / `Error("Project not found")` / `Error("Schedule not found")`, which Remix surfaces as 500 and Sentry's auto-instrumentation captures, creating ongoing noise from real users following stale preview-branch or deleted-resource links. Replaced with a `throwNotFound(statusText)` helper that throws a Response with status 404, matching the established pattern in sibling routes (agents, alerts, bulk-actions, etc.).
+Dashboard runs, sessions, batches, and schedule-detail loaders now return 404 (or redirect to the user's home with a toast for missing projects) instead of 500 when a slug doesn't resolve.