feat(tools/pagure): tracker bridge for Fedora and pagure.io-hosted projects

Add `tools/pagure/` as a tracker bridge for projects hosted on Pagure (pagure.io and self-hosted Pagure deployments). Read + write per the standard bridge contract.

**Suggested capabilities:**

- `issue view/list/search` (read)
- `issue create/edit/close/comment` (write)
- `pull-request view/list` + `pr comment/merge` (write)
- Labels, milestones, custom fields

Write-path discipline: mutations gated on explicit user confirmation in the calling skill.

**Why:** Pagure is the **Fedora project's tracker** — Fedora packaging issues, distro-wide initiatives, Fedora Council, FESCo decisions, and many smaller Red Hat-orbit projects. Without it, a Fedora-aligned adopter (and there are several in the framework's friend network) can't use the skill family on their primary tracker.

**Reference:**

- Pagure API: https://pagure.io/api/0/
- Existing tracker-bridge shape: [`tools/github/`](../tree/main/tools/github/), [`tools/jira/`](../tree/main/tools/jira/)