[codex] fix Windows rollback proof fixture

.github/scripts/check-packaged-agent-proof.py

@@ -2463,13 +2463,47 @@ def plugin_stdio_handoff(
             f"could not derive release target from {archive.name}",
         )
         prior_dir = plugin_data / "codestory-cli" / prior_version
-        prior_bin = prior_dir / "bin" / ("codestory-cli.cmd" if os.name == "nt" else "codestory-cli")
+        prior_bin = prior_dir / "bin" / (
+            "codestory-cli.exe" if os.name == "nt" else "codestory-cli"
+        )
         prior_bin.parent.mkdir(parents=True)
         if os.name == "nt":
-            prior_bin.write_text(
-                f"@echo off\r\nif \"%1\"==\"--version\" (echo codestory-cli {prior_version}& exit /b 0)\r\nexit /b 90\r\n",
+            prior_source = prior_dir / "rollback-version.rs"
+            prior_source.write_text(
+                f'''fn main() {{
+    let args = std::env::args().skip(1).collect::<Vec<_>>();
+    if args.len() == 1 && args[0] == "--version" {{
+        println!("codestory-cli {prior_version}");
+        return;
+    }}
+    std::process::exit(90);
+}}
+''',
                 encoding="utf-8",
             )
+            compiled = subprocess.run(
+                ["rustc", str(prior_source), "-o", str(prior_bin)],
+                text=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+                timeout=timeout_secs,
+                check=False,
+            )
+            require(
+                compiled.returncode == 0 and prior_bin.is_file(),
+                "managed_plugin_convergence",
+                artifact,
+                f"could not compile native rollback fixture: {compiled.stderr}",
+            )
+            pe = prior_bin.read_bytes()
+            pe_offset = int.from_bytes(pe[0x3C:0x40], "little")
+            machine = int.from_bytes(pe[pe_offset + 4 : pe_offset + 6], "little")
+            require(
+                machine == {"windows-x64": 0x8664, "windows-arm64": 0xAA64}.get(target),
+                "managed_plugin_convergence",
+                artifact,
+                f"native rollback fixture machine 0x{machine:04x} did not match {target}",
+            )
         else:
             prior_bin.write_text(
                 f"#!/bin/sh\nif [ \"$1\" = \"--version\" ]; then echo 'codestory-cli {prior_version}'; exit 0; fi\nexit 90\n",

.github/workflows/post-publish-release-smoke.yml

@@ -18,6 +18,7 @@ permissions:
   contents: read
 
 env:
+  RELEASE_RUST_TOOLCHAIN: "1.95.0"
   APPLE_DEVELOPER_TEAM_ID: "PKUJNR8D6F"
 
 jobs:
@@ -154,6 +155,13 @@ jobs:
         shell: pwsh
         run: pwsh -File scripts/install-codestory.ps1 -SelfTest
 
+      - name: Install pinned Rust for Windows rollback proof
+        if: runner.os == 'Windows'
+        shell: pwsh
+        run: |
+          rustup toolchain install "${{ env.RELEASE_RUST_TOOLCHAIN }}" --profile minimal
+          rustup default "${{ env.RELEASE_RUST_TOOLCHAIN }}"
+
       - name: Prove managed plugin handoff
         run: >-
           python .github/scripts/check-packaged-agent-proof.py

CHANGELOG.md

@@ -104,6 +104,9 @@
   rollback. The Codex worktree setup dispatcher now owns one version-checked,
   locked setup path for Windows, macOS, and Linux; the shell and PowerShell
   entrypoints are thin compatibility adapters.
+- Windows packaged upgrade proof now seeds rollback with a native executable
+  fixture, preserving direct-process verification after batch CLI overrides
+  became unsupported.
 - The packaged plugin now launches the CodeStory CLI directly without a shell
   and rejects Windows batch-file overrides. Managed CLI, model, and native
   backend downloads enforce declared byte limits while streaming and remove