fix(installers): 8 critical bugs from gpt-5.5 + glm-5.1 audit (Item 17)

Sub-agents reviewed all 26 installer scripts. Fixed (TDD):

BLOCKERS (install fails on platform):
1. claude/uclaude_uninstall.sh: replace `sed -i` → portable `sedi()` helper
   (BSD sed on macOS requires `-i ''`, GNU uses `-i`). Same fix style as
   codex/ucodex_install.sh:sedi.
2. claude/uclaude_install.ps1: abort if $apiKey null after fetch attempt
   (was silently completing install with broken auth env vars). Guard
   added to all 8 ps1 scripts.
3. qwen/uqwen_install.ps1 + uqwen_update.ps1: build trustedFolders.json
   via [ordered]@{} | ConvertTo-Json (PowerShell single-quoted literal
   was preserving `\"` as backslash+quote, producing INVALID JSON).
4. codex/ucodex_update.ps1: check $LASTEXITCODE after Python patcher call
   (native command non-zero exit doesn't throw under
   ErrorActionPreference='Continue' — patcher failure was silent, no
   PowerShell fallback triggered).

HIGH (wrong behavior / regressions):
5. gemini/ugemini_install.ps1 + update.ps1: read $env:UGEMINI_API_KEY
   FIRST (was only checking $env:UCLAUDE_API_KEY — claude variable).
6. gemini/ugemini_update.ps1: download gemini_config.json from PRIVATE
   unlimitedcoding-config (was downloading from public — would 404 after
   Item 14 sanitization).
7. claude/uclaude_update.ps1: drop ANTHROPIC_API_KEY assignment + dynamic
   models fetch (regression — install.ps1 was fixed earlier but update.ps1
   still set both env vars, re-introducing Auth conflict warning).
8. codex/ucodex_install.sh + update.sh: GitHub API curl needs
   `-H "User-Agent: UnlimitedCoding-Installer"` and `-f` flag (default
   curl/X.Y UA gets 403 from GitHub API + silent fail on 5xx).

Bonus fixes pulled in:
- codex/ucodex_install.ps1: switch codex_config download URL to private
  repo (consistency with update.ps1 + Item 14 sanitization)
- codex/ucodex_install.ps1: add `--all` flag to patcher invocation
  (matched between install + update)

Tests: tests/test_installer_bugs_audit.py — 9 GREEN regression guards.
Total: 186 tests GREEN.

Audit transcripts: gpt-5.5 found 24 issues (claude+gemini), glm-5.1
found 11 issues (codex+qwen). Lower-priority items (heredoc unsafe
quoting, lock files, schema validation) deferred to next iteration.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

claude/uclaude_update.ps1

@@ -74,13 +74,23 @@ Write-Host "  Updated: $oldVer -> $newVer" -ForegroundColor Green
 
 Write-Host "  Setting environment variables..." -ForegroundColor Cyan
 
+# Refresh models list from private config (was hardcoded — went stale weekly).
+$customModels = "claude-opus-4-7,claude-sonnet-4-6,gpt-5.5,gpt-5.4,gpt-5.3-codex,gemini-3.1-pro,gemini-3-flash,glm-5.1"
+try {
+    $cfgResp = Invoke-WebRequest -UseBasicParsing -Uri $configUrl -Headers @{Authorization = "token $configToken"} -TimeoutSec 15
+    $cfgJson = $cfgResp.Content | ConvertFrom-Json
+    if ($cfgJson.models) { $customModels = ($cfgJson.models -join ",") }
+} catch { Write-Warning "Models fetch failed; using fallback list" }
+
+# IMPORTANT: only ANTHROPIC_AUTH_TOKEN (not ANTHROPIC_API_KEY) — setting both
+# triggers Anthropic CLI's "Auth conflict" warning on every claude invocation.
+# uclaude_install.ps1 was fixed earlier; uclaude_update.ps1 had the same bug.
 $envVars = @{
-    "ANTHROPIC_API_KEY"                          = $apiKey
     "ANTHROPIC_AUTH_TOKEN"                       = $apiKey
     "ANTHROPIC_BASE_URL"                         = "https://ai.37-187-136-86.sslip.io"
     "ANTHROPIC_DEFAULT_OPUS_MODEL"               = "claude-opus-4-7"
     "ANTHROPIC_DEFAULT_SONNET_MODEL"             = "claude-sonnet-4-6"
-    "CLAUDE_CUSTOM_MODELS"                       = "claude-opus-4-7,claude-opus-4-6,claude-sonnet-4-6,gpt-5.4,gpt-5.3-codex,gpt-5.2-codex,claude-opus-4-5-20251101,claude-sonnet-4-5-20250929,gemini-3.1-pro-preview,gemini-3-flash-preview,qwen3-coder-plus,qwen3-coder-flash,glm-5,glm-4.7"
+    "CLAUDE_CUSTOM_MODELS"                       = $customModels
     "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC"   = "1"
     "CLAUDE_CODE_DISABLE_FEEDBACK_SURVEY"        = "1"
     "DISABLE_TELEMETRY"                          = "1"
@@ -89,6 +99,10 @@ $envVars = @{
     "CLAUDE_CODE_EFFORT_LEVEL"                   = "high"
 }
 
+# Best-effort cleanup of stale ANTHROPIC_API_KEY (set by older installer)
+[System.Environment]::SetEnvironmentVariable("ANTHROPIC_API_KEY", $null, "User")
+Remove-Item -Path "Env:\ANTHROPIC_API_KEY" -ErrorAction SilentlyContinue
+
 foreach ($k in $envVars.Keys) {
     [System.Environment]::SetEnvironmentVariable($k, $envVars[$k], "User")
     Set-Item -Path "Env:\$k" -Value $envVars[$k]