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/tools.md

@@ -0,0 +1,20 @@
+# Tools
+
+Zed's Agent has access to a variety of tools that allow it to interact with your codebase and perform tasks:
+
+- **`copy_path`**: Copies a file or directory recursively in the project, more efficient than manually reading and writing files when duplicating content.
+- **`create_directory`**: Creates a new directory at the specified path within the project, creating all necessary parent directories (similar to `mkdir -p`).
+- **`create_file`**: Creates a new file at a specified path with given text content, the most efficient way to create new files or completely replace existing ones.
+- **`delete_path`**: Deletes a file or directory (including contents recursively) at the specified path and confirms the deletion.
+- **`diagnostics`**: Gets errors and warnings for either a specific file or the entire project, useful after making edits to determine if further changes are needed.
+- **`edit_file`**: Edits files by replacing specific text with new content.
+- **`fetch`**: Fetches a URL and returns the content as Markdown. Useful for providing docs as context.
+- **`list_directory`**: Lists files and directories in a given path, providing an overview of filesystem contents.
+- **`move_path`**: Moves or renames a file or directory in the project, performing a rename if only the filename differs.
+- **`now`**: Returns the current date and time.
+- **`find_path`**: Quickly finds files by matching glob patterns (like "\*_/_.js"), returning matching file paths alphabetically.
+- **`read_file`**: Reads the content of a specified file in the project, allowing access to file contents.
+- **`grep`**: Searches file contents across the project using regular expressions, preferred for finding symbols in code without knowing exact file paths.
+- **`terminal`**: Executes shell commands and returns the combined output, creating a new shell process for each invocation.
+- **`thinking`**: Allows the Agent to work through problems, brainstorm ideas, or plan without executing actions, useful for complex problem-solving.
+- **`web_search`**: Searches the web for information, providing results with snippets and links from relevant web pages, useful for accessing real-time information.