docs: document MCP resources and prompts support

Update the README's MCP feature entry to cover the full capability trio
(tools, resources, prompts): the capability-gated mcp_read/mcp_prompt
meta-tools, bounded results and blob spilling, and the .prompt REPL
command with staged tab-completion and .list prompts.

Per plans/mcp-resources-prompts-design.md section 10.T9.

README.md

@@ -35,7 +35,9 @@ Coming from [AIChat](https://github.com/sigoden/aichat)? Follow the [migration g
         * [Create Custom TypeScript Tools](https://github.com/Dark-Alex-17/coyote/wiki/Custom-Tools#custom-typescript-based-tools)
         * [Create Custom Bash Tools](https://github.com/Dark-Alex-17/coyote/wiki/Custom-Bash-Tools)
             * [Bash Prompt Utilities](https://github.com/Dark-Alex-17/coyote/wiki/Bash-Prompt-Helpers)
-* [First-Class MCP Server Support](https://github.com/Dark-Alex-17/coyote/wiki/MCP-Servers): Easily connect and interact with MCP servers for advanced functionality.
+* [First-Class MCP Server Support](https://github.com/Dark-Alex-17/coyote/wiki/MCP-Servers): Easily connect and interact with MCP servers for advanced functionality. Coyote supports all three MCP capabilities: tools, resources, and prompts.
+    * Models interact with each server through a compact set of capability-gated meta-tools: `mcp_search`/`mcp_describe` for discovery across tools, resources, and prompts, `mcp_invoke` for tool calls, `mcp_read` for paged and regex-filterable resource reads, and `mcp_prompt` for server-defined prompts. Binary content is spilled to disk instead of inlined, and oversized tool results are bounded before they reach the model.
+    * Invoke server prompts yourself with `.prompt <server> <name> [key=value ...]` in the REPL, with live staged tab-completion (servers, then prompt names, then `key=` arguments), and discover them with `.list prompts`.
 * [Macros](https://github.com/Dark-Alex-17/coyote/wiki/Macros): Automate repetitive tasks and workflows with Coyote "scripts" (macros). Macros are Coyote's custom commands: invoke any macro directly by name (e.g. `.review main`), with tab-completion, right alongside the built-in REPL commands.
     * Give a macro a `description` (shown in `.list macros` and completions) and set `isolated: false` to run its steps on the live session, exactly as if you typed them. Note that non-isolated steps are recorded in the session, and mutating steps (`.role`, `.model`, ...) persist after the macro ends — by design. Steps are fail-fast: an error aborts the remaining steps, but completed steps' effects remain. A non-isolated macro step cannot invoke another macro, and a `.exit` step never exits the REPL.
     * Commit project-specific macros to `.coyote/macros/` in your repo — they shadow same-named global macros (opt out with `--no-workspace-macros`).