fix(env): address P1-P3 review items from code review

- P1: Fix bash completion $cliproxy_profiles scoping — inline profiles
  in env block since variable is only defined at COMP_CWORD=1 scope
- P2: Detect account-based profiles and show specific error message
  instead of generic "not found"
- P2: Show `ccs migrate` hint when unified mode is disabled and settings
  profile resolution fails
- P2: transformToOpenAI omits empty entries at transform time instead of
  relying on output filter (removes fragile coupling)
- P3: Add zsh and auto to --shell completions across all 4 shells; map
  --shell zsh to bash in command handler since syntax is identical
- P3: Auto-detect PowerShell from SHELL containing pwsh on non-Windows
- Tests: 33 pass (+1 pwsh detection test, updated transform assertions)

scripts/completion/ccs.bash

@@ -155,8 +155,8 @@ _ccs_completion() {
   if [[ ${COMP_WORDS[1]} == "env" ]]; then
     case "${prev}" in
       env)
-        # Complete with profile names and flags
-        local env_opts="--format --shell --help -h $cliproxy_profiles"
+        # Complete with profile names and flags (inline profiles since $cliproxy_profiles is out of scope)
+        local env_opts="--format --shell --help -h gemini codex agy qwen"
         if [[ -f ~/.ccs/config.json ]]; then
           env_opts="$env_opts $(jq -r '.profiles | keys[]' ~/.ccs/config.json 2>/dev/null || true)"
         fi
@@ -168,7 +168,7 @@ _ccs_completion() {
         return 0
         ;;
       --shell)
-        COMPREPLY=( $(compgen -W "bash fish powershell" -- ${cur}) )
+        COMPREPLY=( $(compgen -W "auto bash zsh fish powershell" -- ${cur}) )
         return 0
         ;;
       *)

scripts/completion/ccs.fish

@@ -176,7 +176,7 @@ complete -c ccs -n '__fish_seen_subcommand_from doctor' -s h -l help -d 'Show he
 complete -c ccs -n '__fish_seen_subcommand_from env' -l format -d 'Output format'
 complete -c ccs -n '__fish_seen_subcommand_from env; and __fish_seen_argument -l format' -a 'openai anthropic raw' -d 'Format'
 complete -c ccs -n '__fish_seen_subcommand_from env' -l shell -d 'Shell syntax'
-complete -c ccs -n '__fish_seen_subcommand_from env; and __fish_seen_argument -l shell' -a 'bash fish powershell' -d 'Shell'
+complete -c ccs -n '__fish_seen_subcommand_from env; and __fish_seen_argument -l shell' -a 'auto bash zsh fish powershell' -d 'Shell'
 complete -c ccs -n '__fish_seen_subcommand_from env' -s h -l help -d 'Show help for env command'
 
 # ============================================================================

scripts/completion/ccs.ps1

@@ -23,7 +23,7 @@ Register-ArgumentCompleter -CommandName ccs -ScriptBlock {
     $updateFlags = @('--force', '--beta', '--dev', '--help', '-h')
     $envFlags = @('--format', '--shell', '--help', '-h')
     $envFormats = @('openai', 'anthropic', 'raw')
-    $envShells = @('bash', 'fish', 'powershell')
+    $envShells = @('auto', 'bash', 'zsh', 'fish', 'powershell')
     $shellCompletionFlags = @('--bash', '--zsh', '--fish', '--powershell')
     $listFlags = @('--verbose', '--json')
     $removeFlags = @('--yes', '-y')

scripts/completion/ccs.zsh

@@ -128,7 +128,7 @@ _ccs() {
         env)
           _arguments \
             '--format[Output format]:format:(openai anthropic raw)' \
-            '--shell[Shell syntax]:shell:(bash fish powershell)' \
+            '--shell[Shell syntax]:shell:(auto bash zsh fish powershell)' \
             '(- *)'{-h,--help}'[Show help]' \
             '1:profile:($proxy_profiles ${(k)settings_profiles_described})'
           ;;