harden(cli): stop shipping a policy-bypass invocation inside the binary

src/cli/cli.c

@@ -11498,18 +11498,29 @@ int cbm_cmd_update(int argc, char **argv) {
         }
         printf("codebase-memory-mcp update (current: %s)\n\n", CBM_VERSION);
 #ifdef _WIN32
+        /* The printed command deliberately carries NO execution-policy override.
+         * A policy-bypass invocation is one of the most heavily weighted
+         * malicious-script patterns there is, and emitting it as a literal put
+         * that signature inside every Windows artifact we distribute — to save
+         * the user one documented step. Pointing at Unblock-File reaches the
+         * same outcome and leaves the policy decision with them. README's
+         * Windows install section carries the override for the
+         * restricted-policy case: documentation is the right place to hand out
+         * that incantation, a shipped binary is not. */
         printf("The update runs from install.ps1, not from this process. Close any\n"
                "running sessions, then run\n\n");
         if (have_dir) {
-            printf("  powershell -ExecutionPolicy Bypass -File \"%s\\install.ps1\"\n\n", self_dir);
+            printf("  powershell -File \"%s\\install.ps1\"\n\n", self_dir);
         } else {
-            printf("  powershell -ExecutionPolicy Bypass -File install.ps1\n"
+            printf("  powershell -File install.ps1\n"
                    "  (ships in the release archive, and is placed beside the\n"
                    "  binary on install)\n\n");
         }
         printf("It downloads the latest release, verifies its checksum, and replaces\n"
-               "this binary in place. If PowerShell refuses to run the script because\n"
-               "it came from the internet, Unblock-File it first.\n");
+               "this binary in place. If PowerShell refuses to run the script, it is\n"
+               "usually because the file arrived from the internet: run\n"
+               "'Unblock-File install.ps1' first. If your execution policy still\n"
+               "blocks it, the README's Windows install section lists the options.\n");
 #else
         printf("The update runs from install.sh, not from this process. Run\n\n");
         if (have_dir) {

tests/test_windows_bundle_contract.sh

@@ -749,9 +749,20 @@ update_windows_block = (
 require(
     update_start >= 0
     and "install.ps1" in update_windows_block
-    and "powershell -ExecutionPolicy Bypass -File" in update_windows_block,
+    and "powershell -File" in update_windows_block,
     "cbm_cmd_update must print the install.ps1 command on Windows",
 )
+# The printed command must NOT carry an execution-policy override. That is a
+# canonical malicious-loader pattern, and emitting it as a string literal put
+# the signature inside every Windows artifact we ship — to save the user one
+# documented step. The hand-off above is the property this contract cares
+# about; the bypass flag was only ever the literal form it happened to take.
+# Unblock-File covers the common case and the README covers the rest.
+require(
+    "ExecutionPolicy" not in update_windows_block,
+    "cbm_cmd_update must not print an execution-policy override "
+    "(document it instead of shipping the pattern in the binary)",
+)
 require(
     "cbm_windows_launcher" not in cli_source
     and "windows_launcher_state.h" not in cli_source,