docs: trim skill READMEs and ADR/changelog narration

Two related simplification-audit findings, bundled because they edit
some of the same skill-audit files and splitting would fragment
single-file diffs.

Finding 10: delete 48 per-skill/reference README.md files (they
restated SKILL.md in narrative form and no agent ever loads them) plus
2 scaffold templates. Drop the README criterion from skill-audit's
file-structure.md and finding-criteria.md, and the README-generation
step from skill-author's new-skill.sh; update new-skill.bats to match.
Plugin-root READMEs are kept intentionally, out of scope.

Finding 12: strip historical ADR-0020/ADR-0023 citations and
changelog-style narration from model-facing skill content across
kyberforge and git plugin skills. Delete skill-author's one-time
retrofit.md migration guide and its references. Some ADR-0023 tags
were not narration but check-rtk-prefix's required opt-out marker for
intentionally-bare git commands -- those were restored, not stripped.

Mirror re-synced and full pre-commit/pre-push suite verified green.

Refs: SIMPLIFICATION-AUDIT.md findings 10, 12

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YR2CjVumUbEGWcMikcoXBD

plugins/gitea/skills/gitea-prs/README.md

@@ -1,31 +0,0 @@
-# gitea-prs
-
-List, read, create, update, merge, and review Gitea pull requests.
-
-## What it does
-
-This skill handles the pull request lifecycle within the Gitea integration suite — listing and reading PRs (details, diff, changed files, CI status, reviews), creating them (title, body, labels), updating them (title, body, assignees, labels, milestone), adding and removing reviewers, closing/reopening, merging with a chosen strategy and post-merge branch cleanup, and the full code-review flow (create a review with inline comments, submit it, dismiss or delete it, reply to a review comment, and resolve or unresolve a comment thread). It composes `gitea-labels-milestones` for label/milestone ID resolution rather than duplicating that logic — `milestone` applies on an update only, never on create — and defers to `gitea-issues` for anything that turns out to be an issue rather than a PR (they share one number space) and to `gitea-branches`/`gitea-files` for the underlying branch/file operations behind a PR.
-
-## Usage
-
-```text
-/gitea-prs
-```
-
-Describe the PR or review task: list PRs, get a PR's status/diff/reviews, create or update a PR, merge one, or create/submit/dismiss a code review. The skill resolves `owner`/`repo` from the `origin` git remote (or takes them from an orchestrating caller) and resolves any label or milestone names via `gitea-labels-milestones` before writing them.
-
-## Before you start
-
-Requires a Gitea MCP server configured with a token holding `write:issue` + `write:repository`.
-Requires a git remote named `origin` pointing at the Gitea instance, unless an orchestrating caller
-(e.g. `gitea-workflow`) already resolved `owner`/`repo` for you.
-
-## Files
-
-| File | Purpose |
-|------|---------|
-| `SKILL.md` | Skill instructions for agents — Gotchas, the dispatch table, and label/milestone ID resolution via `gitea-labels-milestones` |
-| `references/pull-requests.md` | Execution detail for `list_pull_requests`, `pull_request_read` (get/get_diff/get_files/get_status), and `pull_request_write` (create/update/close/reopen/update_branch/add_reviewers/remove_reviewers) |
-| `references/reviews.md` | Execution detail for `pull_request_review_write` (create/submit/delete/dismiss, plus the comment-thread methods reply_comment/resolve_thread/unresolve_thread) and the review-related `pull_request_read` methods |
-| `references/merging.md` | The merge workflow — CI vs. review/branch-protection gates, merge styles, branch cleanup, and the post-merge issue-close check |
-| `references/sources.md` | Research sources backing the PR/review guidance |