fix(security): catch all-wildcard allow patterns in exec approval policy

ValidateExecApprovalRules rejected single '*' but missed patterns like
'**', '***', '?', '? *', '* ?' that also match any command string.

An agent that can call system.execApprovals.set could bypass the
broad-allow restriction by submitting '**' as an allow pattern:
  {"rules": [{"pattern": "**", "action": "allow"}], "baseHash": "..."}

The glob-to-regex translation turns '**' into '^.*.*$', which matches
every command, exactly like '*' does.

Fix: strip all wildcard chars ('*', '?') and whitespace from the
normalised pattern before checking. If nothing remains the pattern is
an all-wildcard glob and is rejected as broad.  The explicit shell-
prefix checks (powershell *, pwsh *, cmd *, cmd.exe *) are preserved
for patterns that contain meaningful content but are still too broad.

Tests: add **,  ***, ?, '? *', '* ?' to ExecApprovalsSet_RejectsUnsafeAllowRules.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/OpenClaw.Shared/Capabilities/SystemCapability.cs

@@ -630,7 +630,17 @@ public class SystemCapability : NodeCapabilityBase
                 return "Empty allow rule patterns are not permitted.";
 
             var normalized = pattern.ToLowerInvariant();
-            if (normalized is "*" or "* *" or "powershell *" or "pwsh *" or "cmd *" or "cmd.exe *")
+
+            // Catch all-wildcard patterns (e.g. *, **, ?*, * ?) that match any command.
+            // Strip every wildcard character and whitespace; if nothing remains the pattern
+            // is effectively "match everything" and must be blocked regardless of spelling.
+            var nonWildcardContent = normalized.Replace("*", "").Replace("?", "").Trim();
+            if (string.IsNullOrEmpty(nonWildcardContent))
+                return $"Broad allow rule is not permitted: {pattern}";
+
+            // Catch shell-prefixed blanket patterns that match all commands in a given shell
+            // (e.g. "powershell *" allows every PowerShell command).
+            if (normalized is "powershell *" or "pwsh *" or "cmd *" or "cmd.exe *")
                 return $"Broad allow rule is not permitted: {pattern}";
 
             foreach (var dangerous in DangerousAllowPatternFragments)

tests/OpenClaw.Shared.Tests/CapabilityTests.cs

@@ -553,6 +553,11 @@ public class SystemCapabilityTests
 
     [Theory]
     [InlineData("*")]
+    [InlineData("**")]
+    [InlineData("***")]
+    [InlineData("?")]
+    [InlineData("? *")]
+    [InlineData("* ?")]
     [InlineData("cmd *")]
     [InlineData("Remove-Item *")]
     [InlineData("Invoke-WebRequest *")]