fix(shell-scan): handle PowerShell line endings

packages/shell-scan/research/README.md

@@ -50,6 +50,6 @@ Add one syntax class only when representative commands show meaningful opacity.
 | Replace Bash tree-sitter | 1.38 MB grammar, ~69k parity scans/sec | Pure TS, ~149k parity scans/sec | Keep |
 | Replace PowerShell tree-sitter | 0.98 MB grammar + 0.21 MB shared runtime | Pure TS; no Core parser assets | Keep |
 | Combined scanner bundle | 2.57 MB parser assets | 10.1 KB minified, 3.6 KB gzip | Keep |
-| Security hardening | Initial portable subset | 397 scanner tests, 685 assertions, zero known unsafe shell-grammar corpus cases | Keep |
+| Security hardening | Initial portable subset | 400 scanner tests, 689 assertions, zero known unsafe shell-grammar corpus cases | Keep |
 
 The TUI's independent tree-sitter grammar remains for syntax highlighting. Core has no tree-sitter runtime dependency.

packages/shell-scan/research/results.jsonl

@@ -2,4 +2,4 @@
 {"target":"shell-permission-scan","hypothesis":"the same permission-focused scanner design can replace PowerShell tree-sitter","metric":"parser_asset_bytes","before":1188724,"after":0,"decision":"keep","notes":"removed the 983,236-byte PowerShell grammar and 205,488-byte shared runtime from Core; focused tests and CLI asset tests pass"}
 {"target":"shell-permission-scan","hypothesis":"PowerShell safety hardening remains negligible relative to removed parser assets","metric":"scanner_minified_bytes","before":4203,"after":4846,"decision":"keep","notes":"added quote escaping, redirects, malformed input, dynamic execution, scripts/modules, and location guards; gzip is 1,950 bytes and scanner throughput is 349,777/sec"}
 {"target":"shell-permission-scan","hypothesis":"removing hot-path slices and repeated Set allocation improves throughput while simplifying classification","metric":"scans_per_second","before":349777,"after":514076,"decision":"keep","notes":"median of five complete 9-run benchmark invocations after simplification; 113 scanner tests remain green"}
-{"target":"shell-permission-scan","hypothesis":"mutation closure and grammar hardening remain fast and compact enough for permission analysis","metric":"scans_per_second","before":410594,"after":404948,"decision":"keep","notes":"final 9-run benchmark median; 397 scanner tests and 685 assertions pass; bundle is 10,147 bytes minified and 3,615 bytes gzip"}
+{"target":"shell-permission-scan","hypothesis":"mutation closure and grammar hardening remain fast and compact enough for permission analysis","metric":"scans_per_second","before":410594,"after":415493,"decision":"keep","notes":"final 9-run benchmark median; 400 scanner tests and 689 assertions pass; bundle is 10,147 bytes minified and 3,615 bytes gzip"}

packages/shell-scan/src/index.ts

@@ -519,8 +519,10 @@ export function scanPowerShell(input: string): Result {
       if (/^#requires\b/i.test(input.slice(index))) return { kind: "opaque", reason: "dynamic-execution" }
       finishCommand(index)
       comment = true
-      const newline = input.indexOf("\n", index)
+      const endings = [input.indexOf("\n", index), input.indexOf("\r", index)].filter((ending) => ending >= 0)
+      const newline = endings.length > 0 ? Math.min(...endings) : -1
       if (newline === -1) break
+      comment = false
       index = newline
       segment = newline + 1
       continue
@@ -558,7 +560,7 @@ export function scanPowerShell(input: string): Result {
   }
 
   if (quote) return { kind: "opaque", reason: "unterminated-quote" }
-  if (!comment || input.includes("\n")) finishCommand(input.length)
+  if (!comment) finishCommand(input.length)
   if (redirectTarget || invalid || dangling) return { kind: "opaque", reason: "invalid-structure" }
   if (
     dynamic ||
@@ -605,7 +607,8 @@ function shellCommandName(word: string | undefined) {
 }
 
 function knownPowerShellDirectory(word: string) {
-  return /^(?:\$(?:PWD|HOME|PSHOME)|\$env:[A-Za-z_][A-Za-z0-9_]*|\$\{env:[^}]+\})(?:[\\/]|$)/i.test(word)
+  const variable = /^(?:\$(?:PWD|HOME|PSHOME)|\$env:[A-Za-z_][A-Za-z0-9_]*|\$\{env:[^}]+\})(?:[\\/]|$)/i.exec(word)
+  return Boolean(variable) && !word.slice(variable?.[0].length).includes("$")
 }
 
 function powerShellRedirect(input: string, index: number) {

packages/shell-scan/test/adversarial.test.ts

@@ -149,6 +149,8 @@ describe("ShellScan adversarial corpus", () => {
     "pushd Alias:; si harmless Remove-Item; harmless victim",
     "Invoke-`\nExpression 'Remove-Item victim'",
     "<# ignored #> Remove-Item victim",
+    "Set-Location $HOME/$target; Get-ChildItem",
+    "Push-Location $env:TEMP/$target; Get-ChildItem",
   ])("fails closed for secondary PowerShell execution: %s", (input) => {
     expect(ShellScan.scanPowerShell(input).kind).toBe("opaque")
   })

packages/shell-scan/test/scan.test.ts

@@ -173,6 +173,13 @@ describe("ShellScan PowerShell", () => {
     expect(result.commands.map((command) => command.words[0])).toEqual(["Get-ChildItem", "Remove-Item"])
   })
 
+  test("ends comments at carriage returns", () => {
+    const result = ShellScan.scanPowerShell("# comment\rRemove-Item victim")
+    expect(result.kind).toBe("scanned")
+    if (result.kind === "opaque") return
+    expect(result.commands.map((command) => command.words[0])).toEqual(["Remove-Item"])
+  })
+
   test("scans static commands and pipelines", () => {
     expect(ShellScan.scanPowerShell("Get-ChildItem; Write-Output 'done' | Out-File output.txt")).toEqual({
       kind: "scanned",