Revert "Validate fork PR plugins via pull_request_target"

[andrewmumblebee]

Summary

• Reverts Validate fork PR plugins via pull_request_target #100 (merge commit 92c5929), which switched pr-run.yaml from pull_request to pull_request_target, added a concurrency group, explicit PR-head checkout, and env-var-based template interpolation.
• Restores the workflow to its pre-Validate fork PR plugins via pull_request_target #100 state.

Test plan

• Confirm the reverted workflow runs correctly on a test PR

Summary by CodeRabbit

• Chores
  • Updated pull request validation workflows for more consistent and secure execution.
  • Simplified workflow concurrency and checkout behavior.
  • Improved handling of detected plugin paths during validation, deployment, and result reporting.
  • No changes to exported functionality or the end-user experience.

[github-actions]

🧩 Plugin PR Summary

ℹ️ No plugins were modified in this PR.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI (base), Organization UI (inherited)

Review profile: ASSERTIVE

Plan: Pro

Run ID: fe6c6a6e-4c0d-47a8-bf99-b2b9b0add6b8

📥 Commits

Reviewing files that changed from the base of the PR and between 92c5929 and efaea45.

📒 Files selected for processing (1)

• .github/workflows/pr-run.yaml

---

📝 Walkthrough

Walkthrough

The PR workflow now runs on pull_request, removes PR-specific concurrency and explicit head checkout, simplifies CLI setup, and passes detected plugin paths directly to validation, deployment, and summary steps.

Changes

PR workflow execution

Layer / File(s)	Summary
Workflow startup and CLI setup .github/workflows/pr-run.yaml	The workflow uses the pull_request trigger, removes PR-run concurrency settings and explicit head checkout, and simplifies CLI setup.
Plugin path propagation .github/workflows/pr-run.yaml	Validation, deployment, and summary steps read plugin paths directly from detection output instead of PLUGIN_PATHS environment variables.

---

_{Comment @coderabbitai help to get the list of available commands.}