fix(resolution): keep unknown Python import members unresolved (#2040)

Bisect identifies 5eaa6fed (#2034, #1820) as the first bad commit: its Python named-import fallback resolves task.delay() to the task function itself, hiding the queue effect in API steps. Require member resolution before returning a named Python import's target for attribute access.

Keep direct calls, callbacks, constructors, and known members working. Add absolute/relative aliased-import regression coverage without changing the existing steps assertions.

Validation: git bisect with preserved steps test, tsc and copy-assets at every step, CODEGRAPH_KERNEL=0 throughout bisect. 338 tests pass across ui-steps-api-servers, function-ref, rebuilt kernel-tsjs-parity, resolution, and ui-effects. Issue #1820 repro and tsc --noEmit pass.

__tests__/function-ref.test.ts

@@ -1085,6 +1085,56 @@ def static(pool):
     } finally { cg.close(); }
   });
 
+  it.each(['tasks', '.tasks'])('Python imported members do not fall back to their receiver (%s)', async (module) => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-fnref-import-members-'));
+    fs.writeFileSync(path.join(tmpDir, 'tasks.py'), `from celery import shared_task
+@shared_task
+def send_welcome(item_id):
+    return item_id
+class Store:
+    @staticmethod
+    def fetch():
+        return 1
+settings = None
+`);
+    fs.writeFileSync(path.join(tmpDir, 'main.py'), `from ${module} import send_welcome as welcome, Store as Actual, settings
+def direct():
+    welcome(1)
+def callback(pool):
+    pool.submit(welcome, 1)
+def enqueue():
+    welcome.delay(1)
+    welcome.apply_async(args=[1])
+def member_values(pool):
+    pool.submit(welcome.delay, 1)
+    cb = welcome.custom_attribute
+    return [welcome.apply_async]
+def missing_members():
+    Actual.missing()
+    settings.missing()
+def known_member():
+    Actual.fetch()
+def known_callback(pool):
+    pool.submit(Actual.fetch)
+def construct():
+    return Actual()
+`);
+    const cg = CodeGraph.initSync(tmpDir);
+    try {
+      await cg.indexAll();
+      const task = cg.getNodesByName('send_welcome').find(n => n.kind === 'function')!;
+      expect(sourceNames(cg, cg.getIncomingEdges(task.id).filter(e => e.kind === 'calls'))).toEqual(['direct']);
+      expect(sourceNames(cg, fnRefEdgesInto(cg, 'send_welcome'))).toEqual(['callback']);
+      const missing = cg.getNodesByName('missing_members')[0]!;
+      expect(cg.getOutgoingEdges(missing.id).filter(e => e.kind === 'calls' || e.kind === 'instantiates')).toEqual([]);
+      const fetch = cg.getNodesByName('fetch').find(n => n.kind === 'method')!;
+      expect(sourceNames(cg, cg.getIncomingEdges(fetch.id).filter(e => e.kind === 'calls'))).toEqual(['known_member']);
+      expect(sourceNames(cg, fnRefEdgesInto(cg, 'fetch'))).toEqual(['known_callback']);
+      const store = cg.getNodesByName('Store').find(n => n.kind === 'class')!;
+      expect(sourceNames(cg, cg.getIncomingEdges(store.id).filter(e => e.kind === 'instantiates'))).toEqual(['construct']);
+    } finally { cg.close(); }
+  });
+
   it('#1820: same-file ambiguity and noncallable receivers stay unlinked', async () => {
     tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-fnref-ambiguity-'));
     fs.writeFileSync(path.join(tmpDir, 'main.py'), `class A:

src/resolution/import-resolver.ts

@@ -1725,6 +1725,13 @@ export function resolveViaImport(
             // constant edge below rather than fabricating a wrong one.
             const instanceMember = resolveImportedInstanceMember(targetNode, ref, imp.localName, context);
             if (instanceMember) return instanceMember;
+
+            // Finding a named Python import proves the receiver exists, not
+            // its requested attribute. In particular, task.delay() enqueues
+            // work; it does not call the imported task function directly.
+            // Keep unknown members unresolved (including callback values)
+            // instead of falling back to the receiver as their target.
+            if (ref.language === 'python') return null;
           }
 
           return {