fix(dogfood/coder): disable gh terminal color probes (#26114)

Newer GitHub CLI versions probe terminal colors before interactive
prompts, which can leave OSC responses in dogfood web terminal stdin and
break `gh auth login`.

Default `NO_COLOR=1` inside the dogfood `/usr/local/bin/gh` wrappers
when callers have not set it themselves. This avoids the color probe
without pinning or downgrading `gh`, and keeps the existing Coder
external-auth wrapper behavior intact.

Refs ENG-2842.

> 🤖 Generated by Coder Agents on behalf of @johnstcn.

dogfood/coder/ubuntu-22.04/files/usr/local/bin/gh

@@ -10,6 +10,11 @@
 
 REAL_GH="/usr/bin/gh"
 
+# ENG-2842: prevent gh from probing terminal colors before interactive prompts.
+if [ -z "${NO_COLOR+x}" ]; then
+  export NO_COLOR=1
+fi
+
 # If GH_TOKEN or GITHUB_TOKEN is already set, defer to the real gh.
 if [ -n "${GH_TOKEN:-}" ] || [ -n "${GITHUB_TOKEN:-}" ]; then
   exec "$REAL_GH" "$@"

dogfood/coder/ubuntu-26.04/files/usr/local/bin/gh

@@ -10,6 +10,11 @@
 
 REAL_GH="/usr/bin/gh"
 
+# ENG-2842: prevent gh from probing terminal colors before interactive prompts.
+if [ -z "${NO_COLOR+x}" ]; then
+  export NO_COLOR=1
+fi
+
 # If GH_TOKEN or GITHUB_TOKEN is already set, defer to the real gh.
 if [ -n "${GH_TOKEN:-}" ] || [ -n "${GITHUB_TOKEN:-}" ]; then
   exec "$REAL_GH" "$@"