Fix PR Build workflow: add working-directory: cli (#10)

The PR Build workflow was failing because it referenced extension.yaml
and ran azd x build/pack from the repo root instead of the cli/
subdirectory. Added defaults.run.working-directory: cli and explicit
working-directory: cli on steps that need it. Also fixed install
script paths to use cli/scripts/.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jongio

.github/workflows/pr-build.yml

@@ -286,24 +286,24 @@ jobs:
           
           **PowerShell (Windows):**
           \`\`\`powershell
-          iex "& { \$(irm https://raw.githubusercontent.com/$REPO/$BRANCH/scripts/install-pr.ps1) } -PrNumber $PR_NUM -Version $VERSION"
+          iex "& { \$(irm https://raw.githubusercontent.com/$REPO/$BRANCH/cli/scripts/install-pr.ps1) } -PrNumber $PR_NUM -Version $VERSION"
           \`\`\`
           
           **Bash (macOS/Linux):**
           \`\`\`bash
-          curl -fsSL https://raw.githubusercontent.com/$REPO/$BRANCH/scripts/install-pr.sh | bash -s $PR_NUM $VERSION
+          curl -fsSL https://raw.githubusercontent.com/$REPO/$BRANCH/cli/scripts/install-pr.sh | bash -s $PR_NUM $VERSION
           \`\`\`
           
           ### Uninstall
           
           **PowerShell (Windows):**
           \`\`\`powershell
-          iex "& { \$(irm https://raw.githubusercontent.com/$REPO/$BRANCH/scripts/uninstall-pr.ps1) } -PrNumber $PR_NUM"
+          iex "& { \$(irm https://raw.githubusercontent.com/$REPO/$BRANCH/cli/scripts/uninstall-pr.ps1) } -PrNumber $PR_NUM"
           \`\`\`
           
           **Bash (macOS/Linux):**
           \`\`\`bash
-          curl -fsSL https://raw.githubusercontent.com/$REPO/$BRANCH/scripts/uninstall-pr.sh | bash -s $PR_NUM
+          curl -fsSL https://raw.githubusercontent.com/$REPO/$BRANCH/cli/scripts/uninstall-pr.sh | bash -s $PR_NUM
           \`\`\`
           
           ---