feat(gitea): add gitea-branches skill (branches + commits)

Adds plugins/gitea/skills/gitea-branches/ per ADR 0011, covering
list_branches/create_branch/delete_branch (migrated from the flat
plugins/bin/skills/gitea/ dispatch) plus list_commits/get_commit (new
read-only commit-history domain). Call signatures were re-verified live
via ToolSearch against the deployed gitea-mcp server rather than copied
from api-reference.md, per issue #6 comment #849's root-cause fix.

Bumps the gitea plugin to 1.1.0 in both manifests for the new skill.

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

@@ -0,0 +1,35 @@
+# gitea-branches
+
+Manage Gitea repository branches and inspect commit history via the Gitea MCP server.
+
+## What it does
+
+This skill handles branch lifecycle operations (list, create, delete) and read-only commit
+history (list commits, get a single commit's full detail) against a Gitea repository. It resolves
+`owner`/`repo` from the git remote, dispatches to the right MCP tool, and applies safety and
+pagination conventions specific to Gitea's API (e.g. refusing to delete a protected branch without
+explicit confirmation, and treating unexpected 404s as possible masked 403s).
+
+## Before you start
+
+Requires a Gitea MCP server configured with a token. `list_branches`, `list_commits`, and
+`get_commit` work with `write:issue` alone; `create_branch` and `delete_branch` need
+`write:repository`. Requires a git remote named `origin` pointing at the Gitea instance.
+
+## Usage
+
+```
+/gitea-branches
+```
+
+Describe your task: list/create/delete a branch, or list/inspect commits. 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/branches.md` | Verified call signatures and mechanics for list/create/delete branch |
+| `references/commits.md` | Verified call signatures and mechanics for list/get commit |
+| `references/sources.md` | Research sources backing the branch/commit guidance |