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-issues/README.md

@@ -1,51 +0,0 @@
-# gitea-issues
-
-Read and write Gitea issues — list, get, create, comment, close, and search — via the Gitea MCP server.
-
-## What it does
-
-This skill handles the issue lifecycle (`list_issues`, `issue_read`, `issue_write`, `search_issues`):
-listing repo issues, reading a single issue's details/comments/labels, creating an issue, updating
-its state, adding/editing comments, applying labels, and searching issues/PRs across repositories.
-The create flow closes out four enrichments deferred from issue #6 comment #848: label inference
-and milestone assignment (both by composing `gitea-labels-milestones`), an assignee workaround for
-the blocked `get_me` scope, and the "Depends on #N" dependency-linking convention. It supersedes the
-`issue`/`issue <N>`/`issue close <N>`/`issue comment <N>` dispatch this plugin's old single flat
-Gitea skill carried, retired when the plugin was split into per-domain deep modules.
-
-## 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.
-
-## How it composes
-
-This skill composes `gitea-labels-milestones` for *all* label inference, label-name-to-ID
-resolution, and milestone lookup, rather than duplicating that taxonomy or its resolution logic —
-see `references/enrichments.md` for the call protocol. Managing the label and milestone definitions
-themselves (create/edit/delete a label, create/close a milestone) is out of scope here and goes to
-`gitea-labels-milestones` directly.
-
-One boundary the description does not spend characters on, because it was never going to win an
-issue request: local git branch or commit work belongs to `gitea-branches` (Gitea-side) or
-`git-branches` (working copy).
-
-## Usage
-
-```text
-/gitea-issues
-```
-
-Describe your task: list issues, create one, get/comment/close/label a specific issue number, or
-search across repos. See `SKILL.md`'s dispatch table for the full set of recognized invocations.
-
-## Files
-
-| File | Purpose |
-|------|---------|
-| `SKILL.md` | Skill instructions for agents — dispatch table, Gotchas |
-| `references/issues.md` | Verified call signatures and mechanics for `list_issues`/`issue_read`/`issue_write` |
-| `references/search.md` | Verified call signature and mechanics for `search_issues` |
-| `references/enrichments.md` | Create-flow enrichments — label inference, milestone assignment, assignee workaround, dependency-linking convention |
-| `references/sources.md` | Research sources backing the issue guidance |