Codex support, and plainer docs

install.sh / install.ps1 synced from the source repo: they now wire the Codex
runtime where codex is on PATH, with --no-codex / -NoCodex to opt out.

README: say what gets wired and name the Windows flag spellings; drop the
stiffer wording in the licence and service sections; add a table of where the
binary, the data and the service definition actually live, since ~/.standup is
the thing people need to know about for backups and for STANDUP_HOME.

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

install.ps1

@@ -2,7 +2,7 @@
 #
 #   irm https://git.rethinkstudios.io/rethink-software/agent-standups/raw/tag/v0.1.0/install.ps1 | iex
 #
-# Flags (when invoked as a file): -SkillOnly -NoNode -Registry <url> -Yes
+# Flags (when invoked as a file): -SkillOnly -NoNode -NoCodex -Registry <url> -Yes
 # Through `irm | iex` the defaults apply; download it to pass flags.
 #
 # Idempotent: on an installed box it prints status and changes nothing.
@@ -11,6 +11,7 @@
 param(
   [switch]$SkillOnly,
   [switch]$NoNode,
+  [switch]$NoCodex,
   [string]$Registry = 'https://git.rethinkstudios.io/api/packages/rethink-software/npm/',
   [switch]$Yes
 )
@@ -83,6 +84,8 @@ Say "winget      : $(if (Have winget) { 'present' } else { 'not available' })"
 
 $standupBin = if (Have standup) { (Get-Command standup).Source } else { '' }
 Say "standup     : $(if ($standupBin) { $standupBin } else { 'not installed' })"
+$codexBin = (Get-Command codex -ErrorAction SilentlyContinue).Source
+Say "codex       : $(if ($codexBin) { "$codexBin$(if ($NoCodex) { ' (-NoCodex)' })" } else { 'not installed' })"
 $standupHome = if ($env:STANDUP_HOME) { $env:STANDUP_HOME } else { Join-Path $HOME '.standup' }
 Say "config      : $(if (Test-Path (Join-Path $standupHome 'config.toml')) { 'exists' } else { 'absent' })"
 
@@ -240,6 +243,15 @@ if (-not $serviceOnly) {
   & standup install --runtime claude
   if ($LASTEXITCODE -ne 0) { Warn 'runtime install reported a problem; see doctor below' }
 
+  # Codex only where its binary exists: `--runtime codex` writes to
+  # $CODEX_HOME/hooks.json, ~/.agents/skills/ and the project's AGENTS.md, and
+  # leaving marked blocks for a tool that is not installed is worse than
+  # skipping. -NoCodex opts out on a box that does have it.
+  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
 }