readme: fix install via plugin marketplace

The install steps used a non-existent "plugins" settings key, so a fresh
clone loaded nothing. Add .claude-plugin/marketplace.json and document the
supported /plugin marketplace add + /plugin install tea@tea flow.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -0,0 +1,13 @@
+{
+  "name": "tea",
+  "owner": {
+    "name": "naudachu"
+  },
+  "plugins": [
+    {
+      "name": "tea",
+      "source": "./",
+      "description": "Gitea CLI (tea) reference plus a mandatory-login guard. Ships /tea:login, /tea:use, and a PreToolUse hook that blocks any tea command that would touch Gitea without --login."
+    }
+  ]
+}

.gitignore

@@ -1,3 +1,4 @@
 .DS_Store
 .docs/
+.claude/
 tmp/

README.md

@@ -0,0 +1,82 @@
+# tea — Claude Code plugin for the Gitea CLI
+
+A Claude Code plugin that gives Claude a reference for the `tea` CLI and enforces a hard rule: every `tea` command runs under the login **the operator chose**, never one Claude picked.
+
+## What it ships
+
+| Piece | What it does |
+|---|---|
+| `/tea:login` skill | Prompts you to pick a Gitea login and pins it to the project |
+| `/tea:use` skill | Tea CLI reference — loads command docs on demand |
+| `tea-guard` hook | PreToolUse hook that blocks or rewrites every `tea` invocation |
+
+## Prerequisites
+
+- **Claude Code** — CLI, desktop app, or IDE extension
+- **Python 3** — required by the `tea-guard` hook (`python3` must be on `$PATH`)
+- **`tea`** — Gitea's official CLI. Install with `brew install tea` (macOS) or from [gitea.com/gitea/tea/releases](https://gitea.com/gitea/tea/releases)
+- At least one login configured: `tea logins add` (interactive — run it in a terminal, not via Claude)
+
+## Installation
+
+This is a Claude Code plugin — install it through the plugin marketplace, not by hand-editing `settings.json`.
+
+1. Register this repo as a marketplace:
+
+   ```
+   /plugin marketplace add https://git.noodles.cam/claude-skills/tea.git
+   ```
+
+   Already have a local clone? Point at the directory instead:
+
+   ```
+   /plugin marketplace add /path/to/tea
+   ```
+
+2. Install the plugin:
+
+   ```
+   /plugin install tea@tea
+   ```
+
+The skills (`/tea:login`, `/tea:use`) and the `tea-guard` hook load immediately. Use `/plugin` to enable, disable, or update it later.
+
+> The marketplace registration is written to `extraKnownMarketplaces` and the plugin to `enabledPlugins` in your settings automatically — you don't edit those by hand. There is **no** top-level `"plugins"` settings key; if you've added one from older instructions, remove it.
+
+## First use
+
+Run `/tea:login` once per project. Claude will list your available Gitea logins and ask you to pick one. The choice is written to `.claude/settings.local.json` and takes effect immediately — no restart needed.
+
+```
+/tea:login
+```
+
+After that, use `/tea:use` to look up commands, or just ask Claude to do something with Gitea and it will load the reference automatically.
+
+## How the login guard works
+
+Every `tea` invocation Claude writes must carry the literal placeholder `--login "$GITEA_LOGIN"`. The `tea-guard` hook intercepts the Bash call before it runs, looks up the pinned login from `.claude/settings.local.json`, and rewrites the command to use it.
+
+Claude is **blocked** from:
+- running `tea` without `--login` at all
+- naming a login itself (e.g. `--login myaccount`)
+- using any variable other than `$GITEA_LOGIN`
+
+This prevents silent fallback to the machine's default login (often a personal account) when working in a project that belongs to a different identity.
+
+`tea logins list` and `tea --version / --help` are exempt — they don't touch Gitea data.
+
+## Project layout
+
+```
+.claude-plugin/
+  plugin.json                plugin manifest
+  marketplace.json           marketplace catalog (makes `/plugin install` work)
+hooks/
+  hooks.json                 registers the PreToolUse hook
+  tea-guard.sh               the guard (Python 3, no deps)
+skills/
+  login/SKILL.md             /tea:login skill
+  use/SKILL.md               /tea:use skill
+  use/references/tea/        tea CLI reference docs
+```