feat(session): add explicit provider registry and target binding

Introduce deterministic deep-provider discovery and immutable per-target routing while retaining disjoint artifact and native capability families.

Expose provider selection consistently through MCP, CLI, environment configuration, session status, prompt completion, typed diagnostics, and generated documentation. Preserve exact provider/profile provenance without request racing or transparent fallback.

Cover overlapping providers, ambiguity, rejection details, cancellation, restoration, package installation, and real Hopper target switching.

tests/binarySession.test.ts

@@ -558,6 +558,35 @@ describe("binary session", () => {
     expect(created).toBe(1);
   });
 
+  it("cancels legacy profile resolution even when the provider ignores its signal", async () => {
+    const [first] = await targets();
+    const provider = cacheProvider([]);
+    let observedSignal: AbortSignal | undefined;
+    let created = 0;
+    provider.resolveAnalysisProfile = (_target, options) => {
+      observedSignal = options?.signal;
+      return new Promise<never>(() => undefined);
+    };
+    provider.createClient = () => {
+      created += 1;
+      return new TestClient();
+    };
+    const session = new BinarySession(provider);
+    const controller = new AbortController();
+    const opening = session.open(first, { signal: controller.signal });
+    while (observedSignal === undefined)
+      await new Promise<void>((resolve) => setImmediate(resolve));
+    expect(observedSignal).toBe(controller.signal);
+
+    controller.abort();
+
+    await expect(opening).resolves.toMatchObject({
+      ok: false,
+      error: { _tag: "AnalysisCancelledError", operation: "open_binary" },
+    });
+    expect(created).toBe(0);
+  });
+
   it("cancels a call while it waits for a transition", async () => {
     const [first] = await targets();
     const health = deferred<ReturnType<typeof ok>>();