Add dotbot act + label-gated dotbot review GitHub Actions workflows

Summary

Port the dotbot code act and dotbot code review GitHub Actions workflows from the ovh-k8s-cluster repo into dotCMS/core.

Background

The OVH cluster repo runs AI-powered automation via the pinned wezell/openrouter-code-review-action:

• dotbot-act — responds to /dotbot ... comments on PRs with autonomous edits (act mode)
• dotbot-review — runs an autonomous AI code review on PRs (review mode)

For core, the review should not run on every PR (cost/noise) — it should only run when a PR is explicitly labeled PR : dotbot review.

Requirements

• dotbot-act.yml workflow copied verbatim — fires on /dotbot comments on PRs (issue + review comments), excludes dependabot
• dotbot-review.yml workflow gated on the PR : dotbot review label — runs only on labeled PRs, re-runs on subsequent pushes (synchronize) to that PR
• Review fires immediately when the label is applied (include labeled/unlabeled trigger types; concurrency + cancel-in-progress handles label removal)
• Label expression quoted in YAML (label name contains :, invalid in a plain scalar)
• PR : dotbot review label created on the repo

Repo prerequisites (settings, not code)

• OPENROUTER_API_KEY secret set in repo secrets (does not carry over from ovh-k8s-cluster)
• Optional: DOTBOT_REVIEW_MODELS repo variable to override default review models

Implementation

PR: #37162

Start by comparing the dotbot-act and dotbot-review workflows in the ovh-k8s-cluster repository, then inspect PR #37162 and the corresponding .github/workflows changes in dotCMS/core. Done means both workflows meet the listed trigger, label, exclusion, and concurrency requirements, and the PR label is created; repository secrets and variables remain prerequisites.