Release v3.8.33 (#4515)

Release v3.8.33 — full CHANGELOG in the PR body. Blocking gates green (Build, Lint, Unit Tests 8/8, Package Artifact, Quality Gates, Quality Ratchet, Docs Sync, PR Test Policy, test-vitest). Admin-merged over a Node 26 future-compat timer flake (1/4) + an E2E UI flake (3/9) — both verified non-deterministic; full test:unit validated locally (16936 pass).

src/shared/validation/compressionConfigSchemas.ts

@@ -195,6 +195,7 @@ export const compressionSettingsUpdateSchema = z
     ultra: ultraConfigSchema.optional(),
     contextEditing: contextEditingConfigSchema.optional(),
     engines: z.record(z.string(), engineToggleSchema).optional(),
+    enginesExplicit: z.boolean().optional(),
     activeComboId: z.string().nullable().optional(),
   })
   .strict();

src/shared/validation/schemas/combo.ts

@@ -138,6 +138,7 @@ export const comboRuntimeConfigSchema = z
     // falls back to the global `settings.stickyRoundRobinLimit` so the existing
     // knob still controls the default. 0 clamps to 1 (no batching) upstream.
     stickyRoundRobinLimit: z.coerce.number().int().min(0).max(1000).optional(),
+    stickyWeightedLimit: z.coerce.number().int().min(0).max(1000).optional(),
     healthCheckEnabled: z.boolean().optional(),
     healthCheckTimeoutMs: z.coerce.number().int().min(100).max(30000).optional(),
     handoffThreshold: z.coerce.number().min(0.5).max(0.94).optional(),
@@ -145,6 +146,7 @@ export const comboRuntimeConfigSchema = z
     handoffProviders: z.array(z.string().trim().min(1).max(100)).max(10).optional(),
     maxMessagesForSummary: z.coerce.number().int().min(5).max(100).optional(),
     maxComboDepth: z.coerce.number().int().min(1).max(10).optional(),
+    nestedComboMode: z.enum(["flatten", "execute"]).optional(),
     trackMetrics: z.boolean().optional(),
     reasoningTokenBufferEnabled: z.boolean().optional(),
     compressionMode: compressionModeSchema.optional(),

src/shared/validation/settingsSchemas.ts

@@ -292,6 +292,11 @@ export const updateSettingsSchema = z.object({
   lkgpEnabled: z.boolean().optional(),
   // #1311: echo the requested alias/combo name in the response model field (opt-in)
   echoRequestedModelName: z.boolean().optional(),
+  // #4481 layer 2: CCR-style Router.webSearch — when a request carries a native
+  // web_search server tool, route the whole request to this model/provider instead of
+  // the default (for providers that don't implement Anthropic's web_search server tool).
+  // Empty/unset = disabled. Value is a model string ("provider,model" / alias / combo).
+  webSearchRouteModel: z.string().max(200).optional(),
   backgroundDegradation: z.unknown().optional(),
   bruteForceProtection: z.boolean().optional(),
   // Auto-routing settings