Fix CI scanner manifest handoff and fingerprint casing

.github/scripts/CiScanMutation.Tests.ps1

@@ -63,6 +63,14 @@ BeforeAll {
             Find    = '    if (Test-MarkerLikeContent -Value $rawBody) {'
             Replace = '    if ($false) {'
         }
+        # The hidden/control-content rejection is a distinct trusted-boundary
+        # layer from the marker check. Disabling it lets a body carrying an HTML
+        # comment (which the canonical marker also is) or invisible content flow
+        # to the deeper post-injection backstop instead of stopping at the edge.
+        'no-hidden-content-rejection' = @{
+            Find    = '    if ($hiddenReason) {'
+            Replace = '    if ($false) {'
+        }
         # Marker-like match patterns can replay trusted publisher state.
         'no-marker-pattern-rejection' = @{
             Find    = '    if (Test-MarkerLikeContent -Value $matchPattern) {'
@@ -120,6 +128,15 @@ BeforeAll {
         return $Path
     }
 
+    function Test-FixedManifestHandoff {
+        param([Parameter(Mandatory = $true)][string]$Source)
+
+        return $Source -match 'CI_SCAN_MANIFEST_PATH: \$\{\{ runner\.temp \}\}/gh-aw/safe-jobs/agent/manifest_final\.json' -and
+            $Source -match 'argument-free `submit_ci_scan`' -and
+            $Source -notmatch '(?ms)^\s{6}inputs:\s*\r?\n\s{8}(?:manifest|manifest_path):' -and
+            $Source -notmatch 'one `manifest` argument'
+    }
+
     function New-ProbeManifest {
         param(
             [string]$Path,
@@ -306,20 +323,40 @@ Describe 'CI scanner marker mutation coverage' {
 
     It 'mutation "no-duplicate-rejection": a pre-marked body is rejected downstream' {
         $body = "$script:CanonicalMarker`n## Summary`nRecurring sample failure.`n`n## Build Information`n- **Pipeline**: maui-pr`n- **Build ID**: 123456`n`n## Error Message`nAssertion failed"
-        $result = Invoke-ValidatorProbe -Mutation @('no-duplicate-rejection') -Body $body
+        # Both edge-layer rejections (marker-like content and hidden/HTML-comment
+        # content) are disabled so this proves the *post-injection* backstop is
+        # independently load-bearing against duplicate markers.
+        $result = Invoke-ValidatorProbe -Mutation @('no-duplicate-rejection', 'no-hidden-content-rejection') -Body $body
 
         $result.ok | Should -BeFalse
         $result.error | Should -BeLike '*exactly one canonical fingerprint marker*'
     }
 
     It 'mutation "no-duplicate-rejection + no-post-injection-check": duplicate markers would ship' {
         $body = "$script:CanonicalMarker`n## Summary`nRecurring sample failure.`n`n## Build Information`n- **Pipeline**: maui-pr`n- **Build ID**: 123456`n`n## Error Message`nAssertion failed"
-        $result = Invoke-ValidatorProbe -Mutation @('no-duplicate-rejection', 'no-post-injection-check') -Body $body
+        $result = Invoke-ValidatorProbe -Mutation @('no-duplicate-rejection', 'no-hidden-content-rejection', 'no-post-injection-check') -Body $body
 
         $result.ok | Should -BeTrue
         ([regex]::Matches($result.body, '<!-- ci-scan-fingerprint:')).Count | Should -Be 2
     }
 
+    It 'baseline: the real validator rejects a body carrying hidden control content' {
+        $body = "## Summary`nRecurring sample failure.`n`n## Build Information`n- **Pipeline**: maui-pr`n- **Build ID**: 123456`n`n## Error Message`nAssertion failed$([char]0x1B)[31m"
+        $result = Invoke-ValidatorProbe -Body $body
+
+        $result.ok | Should -BeFalse
+        $result.error | Should -BeLike '*must not contain*C0 control character*'
+    }
+
+    It 'mutation "no-hidden-content-rejection": a hidden-content body slips past the boundary' {
+        # A benign HTML comment carries no marker tokens, so only the new
+        # hidden/control-content layer stands between it and publication.
+        $body = "## Summary`nRecurring sample failure.`n`n## Build Information`n- **Pipeline**: maui-pr`n- **Build ID**: 123456`n`n## Error Message`nAssertion failed`n<!-- reviewer will not see this -->"
+        $result = Invoke-ValidatorProbe -Mutation @('no-hidden-content-rejection') -Body $body
+
+        $result.error | Should -Not -BeLike '*HTML comment sequence*'
+    }
+
     It 'baseline: the real validator rejects that same pre-marked body outright' {
         $body = "$script:CanonicalMarker`n## Summary`nRecurring sample failure.`n`n## Build Information`n- **Pipeline**: maui-pr`n- **Build ID**: 123456`n`n## Error Message`nAssertion failed"
         $result = Invoke-ValidatorProbe -Body $body
@@ -403,6 +440,45 @@ Describe 'CI scanner twin discovery mutation coverage' {
         @(Get-CiScanTwin).Count | Should -Be 2
     }
 
+    Describe 'CI scanner fixed manifest handoff mutation coverage' {
+        BeforeAll {
+            $script:WorkflowSources = @(
+                Get-Content -LiteralPath (Join-Path $PSScriptRoot '../workflows/ci-status-main.md') -Raw
+                Get-Content -LiteralPath (Join-Path $PSScriptRoot '../workflows/ci-status-net11.md') -Raw
+            )
+            $script:SafeJobStepsNeedle = "      steps:`n        - name: Require successful agent submission gate"
+        }
+
+        It 'baseline: both twins use the fixed argument-free artifact handoff' {
+            @($script:WorkflowSources | Where-Object { Test-FixedManifestHandoff -Source $_ }).Count |
+                Should -Be 2
+        }
+
+        It 'mutation "nested-string-transport": a manifest tool input fails the handoff invariant' {
+            foreach ($source in $script:WorkflowSources) {
+                $source.Contains($script:SafeJobStepsNeedle) | Should -BeTrue
+                $mutated = $source.Replace(
+                    $script:SafeJobStepsNeedle,
+                    "      inputs:`n        manifest:`n          required: true`n          type: string`n$($script:SafeJobStepsNeedle)")
+
+                $mutated | Should -Not -BeExactly $source
+                (Test-FixedManifestHandoff -Source $mutated) | Should -BeFalse
+            }
+        }
+
+        It 'mutation "agent-selected-path": a manifest_path tool input fails the handoff invariant' {
+            foreach ($source in $script:WorkflowSources) {
+                $source.Contains($script:SafeJobStepsNeedle) | Should -BeTrue
+                $mutated = $source.Replace(
+                    $script:SafeJobStepsNeedle,
+                    "      inputs:`n        manifest_path:`n          required: true`n          type: string`n$($script:SafeJobStepsNeedle)")
+
+                $mutated | Should -Not -BeExactly $source
+                (Test-FixedManifestHandoff -Source $mutated) | Should -BeFalse
+            }
+        }
+    }
+
     It 'mutation "one-twin-omitted": discovery reports a single twin' {
         # Proves the anti-vacuity assertion in Validate-CiScanPublisher.Tests.ps1
         # is load-bearing: dropping a twin changes what discovery returns, so the