docs: Overhaul AI documentation (#29747)

To support the Agentic Editing launch. To dos before merging:

- [ ] Anything marked as `todo!` within `docs/src` (Anyone)
- [x] Check all internal links (Joe)
- Joe: I checked all links and fixed all aside from a few that I
annotated with `todo!` comments
- [ ] Update images (Danilo)
- [ ] Go over / show images of tool cards in agent panel overview
(Danilo)
- [ ] Point billing FAQ to new billing docs (Joe)
- [x] Redirects external links
    - [ ] Needs testing
- [x] Delete old docs
- [ ] Ensure all mentioned bindings use the `{#kb ...}` format and that
they are rendering correctly
- [ ] All agent-related actions are now `agent::` and not `assistant::`
- [x] Mention support of `.rules` files in `rules.md`

Release Notes:

- N/A

---------

Co-authored-by: Joseph T. Lyons <josephtlyons@gmail.com>
Co-authored-by: morgankrey <morgankrey@gmail.com>
Co-authored-by: Smit Barmase <37347831+smitbarmase@users.noreply.github.com>
Co-authored-by: Ben Kunkle <Ben.kunkle@gmail.com>
Co-authored-by: Peter Tripp <peter@zed.dev>
Co-authored-by: Ben Kunkle <ben@zed.dev>
Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>
Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>

docs/src/ai/mcp.md

@@ -0,0 +1,28 @@
+# Model Context Protocol
+
+Zed uses the [Model Context Protocol](https://modelcontextprotocol.io/) to interact with context servers.
+
+> The Model Context Protocol (MCP) is an open protocol that enables seamless integration between LLM applications and external data sources and tools. Whether you're building an AI-powered IDE, enhancing a chat interface, or creating custom AI workflows, MCP provides a standardized way to connect LLMs with the context they need.
+
+Check out the [Anthropic news post](https://www.anthropic.com/news/model-context-protocol) and the [Zed blog post](https://zed.dev/blog/mcp) for an introduction to MCP.
+
+## Try it out
+
+Want to try it for yourself? Here are some MCP servers available as Zed extensions:
+
+- [Postgres](https://github.com/zed-extensions/postgres-context-server)
+- [GitHub](https://github.com/LoamStudios/zed-mcp-server-github)
+- [Puppeteer](https://github.com/zed-extensions/mcp-server-puppeteer)
+- [BrowserTools](https://github.com/mirageN1349/browser-tools-context-server)
+- [Brave Search](https://github.com/zed-extensions/mcp-server-brave-search)
+- [Prisma](https://github.com/aqrln/prisma-mcp-zed)
+- [Framelink Figma](https://github.com/LoamStudios/zed-mcp-server-figma)
+- [Linear](https://github.com/LoamStudios/zed-mcp-server-linear)
+
+Browse all available MCP extensions either on [Zed's website](https://zed.dev/extensions?filter=context-servers) or directly in Zed via the `zed: extensions` action in the Command Palette.
+
+## Bring your own context server
+
+If there's an existing MCP server you'd like to bring to Zed, check out the [context server extension docs](../extensions/context-servers.md) for how to make it available as an extension.
+
+If you are interested in building your own MCP server, check out the [Model Context Protocol docs](https://modelcontextprotocol.io/introduction#get-started-with-mcp) to get started.