feat: add inbound media understanding

Co-authored-by: Tristan Manchester <tmanchester96@gmail.com>

src/media-understanding/scope.test.ts

@@ -0,0 +1,46 @@
+import { describe, expect, it } from "vitest";
+import { resolveMediaUnderstandingScope } from "./scope.js";
+
+describe("resolveMediaUnderstandingScope", () => {
+  it("defaults to allow when scope is undefined", () => {
+    expect(resolveMediaUnderstandingScope({})).toBe("allow");
+  });
+
+  it("uses first matching rule", () => {
+    const decision = resolveMediaUnderstandingScope({
+      scope: {
+        default: "deny",
+        rules: [
+          { action: "allow", match: { channel: "whatsapp" } },
+          { action: "deny", match: { channel: "whatsapp", chatType: "direct" } },
+        ],
+      },
+      channel: "whatsapp",
+      chatType: "direct",
+      sessionKey: "whatsapp:direct:123",
+    });
+    expect(decision).toBe("allow");
+  });
+
+  it("matches keyPrefix when provided", () => {
+    const decision = resolveMediaUnderstandingScope({
+      scope: {
+        default: "deny",
+        rules: [{ action: "allow", match: { keyPrefix: "agent:main:" } }],
+      },
+      sessionKey: "agent:main:whatsapp:group:123",
+    });
+    expect(decision).toBe("allow");
+  });
+
+  it("matches keyPrefix case-insensitively", () => {
+    const decision = resolveMediaUnderstandingScope({
+      scope: {
+        default: "deny",
+        rules: [{ action: "allow", match: { keyPrefix: "agent:main:" } }],
+      },
+      sessionKey: "AGENT:MAIN:WHATSAPP:GROUP:123",
+    });
+    expect(decision).toBe("allow");
+  });
+});