fix(ssh): cite the real command-line budget and reuse the cmd.exe ceiling

src/main/providers/windows-shell-args.ts

@@ -14,7 +14,8 @@ import {
 } from '../powershell-osc133-bootstrap'
 import { quoteStartupArg } from '../../shared/tui-agent-startup-shell'
 
-const CMD_EXE_COMMAND_LINE_MAX_CHARS = 8191
+/** cmd.exe's own documented ceiling; callers that go through sshd budget below it. */
+export const CMD_EXE_COMMAND_LINE_MAX_CHARS = 8191
 const STARTUP_COMMAND_TEXT_MAX_CHARS = 6000
 const POWERSHELL_ENCODED_COMMAND_ARG_MAX_CHARS = 28_000
 const CMD_UTF8_SETUP_COMMAND = 'chcp 65001 > nul'

src/main/ssh/ssh-remote-powershell.ts

@@ -1,12 +1,14 @@
 import { gunzipSync, gzipSync } from 'node:zlib'
 import { encodePowerShellCommand } from '../../shared/powershell-command-encoding'
-import { CMD_EXE_MAX_COMMAND_LINE_CHARS } from '../../shared/windows-command-line-budget'
+import { CMD_EXE_COMMAND_LINE_MAX_CHARS } from '../providers/windows-shell-args'
 export {
   quotePowerShellLiteral as powerShellLiteral,
   quotePowerShellNativeArgument as powerShellNativeArg
 } from '../../shared/powershell-native-argument'
 
-// Margin for the `/c` wrapper sshd puts around the command before cmd.exe counts it.
+// Why cmd.exe and not the 32767 CreateProcess cap: Windows OpenSSH runs every exec request
+// through sshd's DefaultShell, cmd.exe on a stock install. Budget under cmd.exe's own ceiling
+// to leave room for the `/c` wrapper sshd adds before cmd.exe counts the line.
 const WINDOWS_REMOTE_COMMAND_LINE_BUDGET_CHARS = 8_000
 
 export function powerShellCommand(script: string): string {
@@ -19,7 +21,7 @@ export function powerShellCommand(script: string): string {
   const compressed = encodedPowerShellCommand(selfExtractingPowerShellScript(script))
   if (compressed.length > WINDOWS_REMOTE_COMMAND_LINE_BUDGET_CHARS) {
     throw new Error(
-      `Remote Windows command needs ${compressed.length} characters; sshd's cmd.exe refuses more than ${CMD_EXE_MAX_COMMAND_LINE_CHARS}.`
+      `Remote Windows command needs ${compressed.length} characters; Orca budgets ${WINDOWS_REMOTE_COMMAND_LINE_BUDGET_CHARS} for a line sshd hands to cmd.exe, which itself refuses more than ${CMD_EXE_COMMAND_LINE_MAX_CHARS}.`
     )
   }
   return compressed

src/main/ssh/ssh-remote-windows-command-line-limit.test.ts

@@ -1,6 +1,6 @@
 import { gunzipSync } from 'node:zlib'
 import { describe, expect, it } from 'vitest'
-import { CMD_EXE_MAX_COMMAND_LINE_CHARS } from '../../shared/windows-command-line-budget'
+import { CMD_EXE_COMMAND_LINE_MAX_CHARS } from '../providers/windows-shell-args'
 import { getRemoteHostPlatform } from './ssh-remote-platform'
 import { tryStealInstallLockCommand } from './ssh-relay-install-lock-commands'
 import { decodeRemotePowerShellScript, powerShellCommand } from './ssh-remote-powershell'
@@ -40,7 +40,7 @@ describe('Windows remote command line limit', () => {
       tryStealInstallLockCommand(windows, 'C:\\Users\\orca\\.orca-remote\\relay', 1_200)
     ]
   ])('keeps the %s command inside what sshd\u2019s cmd.exe accepts', (_name, command) => {
-    expect(command.length).toBeLessThanOrEqual(CMD_EXE_MAX_COMMAND_LINE_CHARS)
+    expect(command.length).toBeLessThanOrEqual(CMD_EXE_COMMAND_LINE_MAX_CHARS)
   })
 
   it('leaves a command that already fits byte-identical', () => {
@@ -54,7 +54,7 @@ describe('Windows remote command line limit', () => {
       (_unused, index) => `Write-Output ${index}; $slot = 'C:\\Users\\orca\\stage-${index}'`
     ).join('\n')
     const command = powerShellCommand(script)
-    expect(command.length).toBeLessThanOrEqual(CMD_EXE_MAX_COMMAND_LINE_CHARS)
+    expect(command.length).toBeLessThanOrEqual(CMD_EXE_COMMAND_LINE_MAX_CHARS)
     expect(decodeRemotePowerShellScript(command)).toBe(script)
     const bootstrap = Buffer.from(
       command.match(/-EncodedCommand\s+([A-Za-z0-9+/=]+)$/u)?.[1] ?? '',
@@ -72,7 +72,7 @@ describe('Windows remote command line limit', () => {
       return String.fromCharCode(97 + (seed % 26))
     }).join('')
     expect(() => powerShellCommand(`Write-Output '${incompressible}'`)).toThrow(
-      /sshd's cmd\.exe refuses more than 8191/u
+      /Orca budgets 8000 for a line sshd hands to cmd\.exe/u
     )
   })
 })

src/shared/windows-command-line-budget.ts

@@ -14,18 +14,6 @@
  */
 export const MAX_COMMAND_LINE_CHARS = 30_000
 
-/**
- * The much smaller cap that applies once cmd.exe is in the chain.
- *
- * cmd.exe refuses a longer line outright — exit 1 and a localized "The command
- * line is too long" — and it is in the chain more often than it looks: Windows
- * OpenSSH runs every exec request through sshd's `DefaultShell`, which is
- * cmd.exe on a stock install. So a command Orca sends to a Windows SSH host is
- * charged this budget, not the 32767 one, and `-EncodedCommand` spends 2.67
- * characters per script character on the way there.
- */
-export const CMD_EXE_MAX_COMMAND_LINE_CHARS = 8_191
-
 /**
  * What `CreateProcess` will count.
  *