Codex is wired up where codex is installed

Synced from the source repo. install.sh and install.ps1 now run
`standup install --runtime codex` machine-wide where codex is on PATH,
with --no-codex / -NoCodex to opt out, and name the per-project
AGENTS.md step in their closing lines.

Signed-off-by: disqualifier <dev@disqualifier.me>

install.ps1

@@ -243,6 +243,15 @@ if (-not $serviceOnly) {
   & standup install --runtime claude
   if ($LASTEXITCODE -ne 0) { Warn 'runtime install reported a problem; see doctor below' }
 
+  # Codex where its binary exists. Machine-wide: the skill and the hooks. The
+  # AGENTS.md step needs a project and is skipped here -- named in the closing
+  # lines instead. Not run at all without codex, so no marked blocks are left
+  # for a tool that is not installed; -NoCodex opts out where it is.
+  if (-not $NoCodex -and $codexBin) {
+    & standup install --runtime codex
+    if ($LASTEXITCODE -ne 0) { Warn 'codex runtime install reported a problem; see doctor below' }
+  }
+
   if ($probe -and -not $probe.HasExited) { Stop-Process -Id $probe.Id -Force -ErrorAction SilentlyContinue }
   Remove-Item -Recurse -Force $probeDir -ErrorAction SilentlyContinue
 }
@@ -300,13 +309,11 @@ Write-Host ''
 & standup code
 Write-Host ''
 Write-Host 'Next: cd <your project>; standup create'
-# Codex's runtime is per-project -- one of its three targets is the project's
-# own AGENTS.md -- so the installer cannot wire it from here: there is no
-# project yet, and the runtime step's throwaway is deleted. Name the command
-# instead, only where codex exists and the user has not opted out.
 if (-not $NoCodex -and $codexBin) {
   Write-Host ''
-  Write-Host 'Codex is installed here. In each project you want it in:'
-  Write-Host '  standup install --runtime codex    # hooks, skill, a block in AGENTS.md'
+  Write-Host 'Codex: the skill and hooks are wired machine-wide. Codex must TRUST them:'
+  Write-Host '  run /hooks inside Codex and approve.'
+  Write-Host 'Per project, for the room rules in AGENTS.md:'
+  Write-Host '  standup install --runtime codex'
 }
 }