feat: add git-commit-signing module (#94)

* feat: add git-commit-signing module

* feat(git-commit-signing): check for git and jq

* fix(git-commit-signing): only use icon once

* fix(git-commit-signing): fix typo in README

Co-authored-by: Muhammad Atif Ali <matifali@live.com>

* bun fmt

* chore: clarify readme SSH key paragraph

* fix: add `curl` as dependency

* feat: download keys to ~/.ssh/git-commit-signing

* feat: add conflict disclaimer

---------

Co-authored-by: Muhammad Atif Ali <matifali@live.com>
Co-authored-by: Atif Ali <atif@coder.com>

git-commit-signing/run.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env sh
+
+if ! command -v git > /dev/null; then
+        echo "git is not installed"
+        exit 1
+fi
+
+if ! command -v curl > /dev/null; then
+        echo "curl is not installed"
+        exit 1
+fi
+
+if ! command -v jq > /dev/null; then
+        echo "jq is not installed"
+        exit 1
+fi
+
+mkdir -p ~/.ssh/git-commit-signing
+
+echo "Downloading SSH key"
+
+ssh_key=$(curl --request GET \
+        --url "${CODER_AGENT_URL}api/v2/workspaceagents/me/gitsshkey" \
+        --header "Coder-Session-Token: ${CODER_AGENT_TOKEN}")
+
+jq --raw-output ".public_key" > ~/.ssh/git-commit-signing/coder.pub <<EOF
+$ssh_key
+EOF
+
+jq --raw-output ".private_key" > ~/.ssh/git-commit-signing/coder <<EOF
+$ssh_key
+EOF
+
+chmod -R 400 ~/.ssh/git-commit-signing/coder
+chmod -R 400 ~/.ssh/git-commit-signing/coder.pub
+
+echo "Configuring git to use the SSH key"
+
+git config --global gpg.format ssh
+git config --global commit.gpgsign true
+git config --global user.signingkey ~/.ssh/git-commit-signing/coder