docs: baked a lot of API docs

docs/API/shell.md

@@ -7,4 +7,33 @@ references:
 
 The Shell API provides functions for running shell commands and interacting with processes.
 
-${spacelua.renderApiDocumentation("shell")}
+<!--#lua spacelua.renderApiDocumentation("shell") -->
+## shell.run
+
+`shell.run(command, arguments, stdin?)`
+
+Runs a shell command on the server and returns its output.
+
+**Parameters:**
+
+- `command` (`string`) — Executable name.
+- `arguments` (`table`) — Command arguments.
+- `stdin?` (`string`) — Text supplied on standard input.
+
+**Returns:**
+
+- `table` — stdout, stderr, and numeric exit code.
+
+**Examples:**
+
+```lua
+local result = shell.run("ls", {"-l"})
+print(result.stdout)
+```
+
+```lua
+local result = shell.run("cat", {}, "hello")
+print(result.stdout)
+```
+<!--/lua-->
+