feat(python): command runner and modify wrappers (doc.command, doc.modify)

HostApi::run_command drives the real OCS command through the same primitives
the automation channel uses, synchronously on the host thread: run a line,
start a command and answer point/text/token/entity/selection/enter prompts, or
cancel (closing anything the command opened). Refused while another command is
active, for a denylist (QUIT, NEW, OPEN, SAVE*, PY_* ...) and off the active tab.
Python: doc.command, doc.start_command and doc.modify (offset, trim, extend,
fillet, move, copy, rotate, scale, mirror, erase). Real-IPC audit checks exact
geometry for every wrapper plus guards and undo; IPC and Python unit tests; docs.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

crates/ocs_plugin_api/src/host.rs

@@ -85,6 +85,56 @@ pub enum SolidBoolean {
     Intersect,
 }
 
+/// One step of driving an OCS command from a script (API v7, additive). The
+/// host runs the real command, so every tool behaves exactly as at the command
+/// line, and answers with where the command stands.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub enum CommandRequest {
+    /// Run a whole command line (`OFFSET 5 ...`): the tokens after the name
+    /// answer the prompts in order and a final Enter finishes the command.
+    Run { line: String },
+    /// Start a command and leave it waiting for its first input.
+    Start { name: String },
+    /// Answer the current prompt with a world-coordinate point.
+    Point { point: [f64; 3] },
+    /// Answer with typed text (a distance, an angle, a name).
+    Text { text: String },
+    /// Answer with a keyword option.
+    Token { text: String },
+    /// Pick an entity at a point.
+    Entity { handle: Handle, point: [f64; 3] },
+    /// Complete an object-selection prompt with the current selection.
+    Selection,
+    /// Press Enter.
+    Enter,
+    /// Cancel the running command and close anything it left open.
+    Cancel,
+}
+
+/// Where a command stands after a [`CommandRequest`].
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
+pub struct CommandOutcome {
+    /// `completed` when nothing is waiting, `waiting_input` when the command
+    /// (or an editor or dialog it opened) needs more.
+    pub status: String,
+    /// What is still open: `command`, `text_editor`, `mtext_editor` or `modal:<kind>`.
+    pub blocked_by: Option<String>,
+    /// The waiting command's name and prompt (empty when none).
+    pub command: String,
+    pub prompt: String,
+    /// The kinds of input the prompt accepts (`point`, `entity`, `selection`,
+    /// `text`, `token`, `enter`) and its keyword options.
+    pub accepts: Vec<String>,
+    pub options: Vec<String>,
+    /// Entities in the drawing after the step, and the change.
+    pub entities: u64,
+    pub added: i64,
+    /// Typed tokens no prompt asked for.
+    pub unconsumed: Vec<String>,
+    /// The command line's error message when the step failed.
+    pub error: Option<String>,
+}
+
 /// A change to a drawing table record (API v7, additive). The host validates
 /// the request, records one undo step and refuses without changing anything
 /// when it cannot honour it; the result is the record's handle.
@@ -808,6 +858,13 @@ pub trait HostApi {
         Err("solid operations are not supported by this host".to_owned())
     }
 
+    /// Drive an OCS command from a script (API v7, additive). Refused, with
+    /// nothing run, when another command is already active or the request names
+    /// a command that could end the session or re-enter the plugin.
+    fn run_command(&mut self, _request: CommandRequest) -> Result<CommandOutcome, String> {
+        Err("running commands is not supported by this host".to_owned())
+    }
+
     /// Create, change, rename, delete or select a drawing table record (API v7,
     /// additive). Returns the record's handle; a refusal changes nothing.
     fn table_operation(&mut self, _operation: TableOperation) -> Result<Handle, String> {