Add resumable LLM investigation loop with bounded controller execution

tests/test_package_reader.py

@@ -3,6 +3,35 @@ import pytest
 from viano_bug_analysis.package import PackageReader, PackageReadError
 
 
+def test_open_reader_uses_immutable_snapshot(make_package):
+    path=make_package(entries={"data":b"original"})
+    with PackageReader(path) as reader:
+        path.write_bytes(b"damaged after opening")
+        assert reader.read_bytes("data")==b"original"
+    with pytest.raises(PackageReadError):
+        with PackageReader(path):pass
+
+
+def test_cached_validation_is_detached_and_limits_are_part_of_key(make_package):
+    from viano_bug_analysis.package import PackageLimits
+    path=make_package(entries={"data":b"original"})
+    with PackageReader(path) as reader:
+        reader._result.manifest["case_id"]="mutated-private-result"
+    with PackageReader(path) as reader:assert reader.manifest["case_id"]=="case-A"
+    with pytest.raises(PackageReadError):
+        with PackageReader(path,PackageLimits(max_file_bytes=1)):pass
+
+
+def test_cached_reader_rejects_changed_bytes_even_when_mtime_and_size_match(make_package):
+    import os
+    path=make_package(entries={"data":b"original"})
+    with PackageReader(path):pass
+    stat=path.stat();path.write_bytes(b"x"*stat.st_size)
+    os.utime(path,ns=(stat.st_atime_ns,stat.st_mtime_ns))
+    with pytest.raises(PackageReadError):
+        with PackageReader(path):pass
+
+
 def test_read_only_and_filename_independent(make_package):
     path = make_package(entries={"unknown/data.bin": b"\x00\xff"})
     before = path.read_bytes()