bin: add the coder CLI

Pinned to v2.36.5 (latest release). Same shape as the other tarball
installs: the asset drops the tag's leading v and the binary sits at the
archive root. Verified on this box: installs, `coder version` reports
v2.36.5, and a re-run skips it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -45,7 +45,8 @@ Already have a clone? Just run it directly:
   kubectx/kubens, stern, yq, OpenTofu, terragrunt, task (go-task, the
   Taskfile runner), the 1Password CLI `op` for secrets storage, the
   opencode coding agent, zarf (DevSecOps for Offline and Airgapped
-  Kubernetes), and packer (HashiCorp's infrastructure build tool).
+  Kubernetes), packer (HashiCorp's infrastructure build tool), and the
+  coder CLI for Coder workspaces.
   kind is installed only when full (non-rootless) Docker is available —
   it doesn't work against rootless Docker, so it is skipped on Kasm.
   No sudo, nothing outside `$HOME`, so tools persist across Kasm

bin/install.sh

@@ -204,6 +204,17 @@ install_terragrunt() {
   mark_version terragrunt "$ver"
 }
 
+# coder — CLI for Coder workspaces (coder login, coder ssh, coder config-ssh).
+# Release tag is vX but asset drops the v; binary is at the archive root.
+install_coder() {
+  ver=2.36.5
+  have_version coder "$ver" && { fsay "coder $ver already installed."; return 0; }
+  install_tarball_bin \
+    "https://github.com/coder/coder/releases/download/v$ver/coder_${ver}_linux_$DEB.tar.gz" \
+    coder coder
+  mark_version coder "$ver"
+}
+
 # try <install_fn> — run one tool's installer; on failure, warn and keep going.
 #
 # WHY: these installs used to be bare calls, so under `set -eu` the FIRST
@@ -242,6 +253,7 @@ try install_1p
 try install_opencode
 try install_zarf
 try install_packer
+try install_coder
 
 if [ -n "$FAILED" ]; then
   fsay ""