Remove the unreleased Antigravity provider plugin (#5781)

* refactor(providers): remove the unreleased Antigravity plugin

Remove the provider at the owner’s request because headless command approvals are unsupported. Preserve Muse, shared plugin infrastructure, and earlier editor and terminal integrations.

* test(plugins): keep builtin startup coverage generic

public-docs/providers.md

@@ -8,7 +8,7 @@ category: Providers
 
 # Providers
 
-Paseo doesn't ship its own coding agent. It launches and supervises **existing CLIs you've already installed and authenticated**, Claude Code, Codex, OpenCode, Antigravity, Muse Code, Cursor, Gemini, and the rest. Your subscriptions, your config, your skills, your MCP servers all stay intact. Paseo just gives you a UI, a CLI, a relay, and orchestration on top.
+Paseo doesn't ship its own coding agent. It launches and supervises **existing CLIs you've already installed and authenticated**, Claude Code, Codex, OpenCode, Muse Code, Cursor, Gemini, and the rest. Your subscriptions, your config, your skills, your MCP servers all stay intact. Paseo just gives you a UI, a CLI, a relay, and orchestration on top.
 
 ## Mental model
 
@@ -16,7 +16,7 @@ A provider is the contract between Paseo and one external agent CLI: how to laun
 
 ## Two tiers
 
-- **Native support**, Paseo ships a bundled adapter for the major agents (Claude Code, Codex, OpenCode, Pi, [Antigravity](/docs/supported-providers#antigravity), [Muse Code](/docs/muse-code)). Auto-discovered when the underlying CLI is installed, with mode metadata and voice support where applicable.
+- **Native support**, Paseo ships a bundled adapter for the major agents (Claude Code, Codex, OpenCode, Pi, [Muse Code](/docs/muse-code)). Auto-discovered when the underlying CLI is installed, with mode metadata and voice support where applicable.
 - **ACP catalog**, any agent speaking the [Agent Client Protocol](https://agentclientprotocol.com) is supported through a generic adapter. Paseo ships a curated catalog of one-click installs (Cursor, Gemini, GitHub Copilot, Hermes, Kimi, Qwen Code, and 25+ more), and you can add any other ACP agent yourself.
 
 Either way, **you install the underlying CLI**. Paseo runs it.

public-docs/supported-providers.md

@@ -18,39 +18,8 @@ Work out of the box once the underlying CLI is installed and authenticated.
 - [Codex](/docs/codex). OpenAI's workspace agent with sandbox controls and optional network access.
 - [OpenCode](https://opencode.ai/). Open-source coding assistant with multi-provider model support.
 - [Pi](https://pi.dev). Minimal terminal-based coding agent with multi-provider LLM support.
-- [Antigravity](#antigravity). Uses your installed `agy` CLI through a built-in provider plugin.
 - [Muse Code](/docs/muse-code). Meta's terminal coding agent, bundled as a provider plugin.
 
-### Antigravity
-
-Install the Antigravity CLI (`agy`) on your daemon host, then run `agy` once to sign in. Pick
-**Antigravity** in Paseo. The provider ships with Paseo; no separate plugin install is required.
-
-**Default**, **Accept edits**, and **Plan** allow workspace edits and deny shell commands.
-**Full access** allows everything. Plan does not enforce read-only access. To run a denied shell
-command, choose Full access and send another prompt.
-
-Paseo MCP tools and steering are unavailable. Your own `agy` MCP servers still work. Attached
-images are passed as file references for the agent to read.
-
-If `agy` is outside your daemon's PATH, override its command in `~/.paseo/config.json`. Use `env`
-for provider-specific environment variables:
-
-```json
-{
-  "agents": {
-    "providers": {
-      "antigravity": {
-        "command": ["/absolute/path/to/agy"],
-        "env": { "EXAMPLE_VARIABLE": "value" }
-      }
-    }
-  }
-}
-```
-
-See [Custom providers](/docs/custom-providers) for command and environment overrides.
-
 ## ACP catalog
 
 Pick any of these from the in-app provider catalog. Each entry is a one-click install of the underlying CLI.