feat(core): add command, intent, and routing primitives

src/routing/policy.ts

@@ -0,0 +1,64 @@
+export type RoutingPath = 'fast' | 'llm';
+
+export interface RoutingPolicyConfig {
+  enabled: boolean;
+  fastPathThreshold: number;
+  llmThreshold: number;
+  defaultPath: RoutingPath;
+}
+
+export interface RoutingDecisionInput {
+  confidence: number | null;
+}
+
+export interface RoutingDecision {
+  path: RoutingPath;
+  reason: 'disabled' | 'no_match' | 'high_confidence' | 'low_confidence' | 'mid_confidence';
+}
+
+export class RoutingPolicy {
+  private readonly config: RoutingPolicyConfig;
+
+  constructor(config: RoutingPolicyConfig) {
+    this.config = config;
+  }
+
+  isEnabled(): boolean {
+    return this.config.enabled;
+  }
+
+  decide(input: RoutingDecisionInput): RoutingDecision {
+    if (!this.config.enabled) {
+      return {
+        path: this.config.defaultPath,
+        reason: 'disabled',
+      };
+    }
+
+    if (input.confidence === null) {
+      return {
+        path: this.config.defaultPath,
+        reason: 'no_match',
+      };
+    }
+
+    if (input.confidence >= this.config.fastPathThreshold) {
+      return {
+        path: 'fast',
+        reason: 'high_confidence',
+      };
+    }
+
+    if (input.confidence <= this.config.llmThreshold) {
+      return {
+        path: 'llm',
+        reason: 'low_confidence',
+      };
+    }
+
+    return {
+      path: this.config.defaultPath,
+      reason: 'mid_confidence',
+    };
+  }
+}