feat: support Agent Window sizing (session start --width/--height, window resize) (#52)

- `bsk session start --width <px> --height <px>` opens the Agent Window
  with the given outer size (chrome.windows.create)
- new `bsk window resize --session <id> --width <px> --height <px>`
  resizes the Agent Window at runtime (chrome.windows.update)
- both validated on CLI, daemon and extension sides (100..=7680 CSS px)
- protocol: new tool.window_resize method (BrowserMutation) and
  optional width/height on tool.session_start params; schemas regenerated

crates/bsk-cli/src/cli/window.rs

@@ -0,0 +1,103 @@
+//! `bsk window …` subcommands — Agent Window management.
+
+use std::path::PathBuf;
+
+use anyhow::Context;
+use bsk_protocol::Method;
+use bsk_protocol::tools::{WindowResizeParams, WindowResizeResult};
+use clap::{Args, Subcommand};
+
+use crate::cli::TOOL_IPC_TIMEOUT;
+use crate::cli::ensure_daemon::ensure_daemon;
+use crate::cli::error::{CliError, Format};
+
+#[derive(Debug, Clone, Args)]
+pub struct WindowCmd {
+    #[command(subcommand)]
+    pub sub: WindowSub,
+}
+
+#[derive(Debug, Clone, Subcommand)]
+pub enum WindowSub {
+    /// Resize the session's Agent Window.
+    Resize(WindowResizeArgs),
+}
+
+#[derive(Debug, Clone, Args)]
+pub struct WindowResizeArgs {
+    /// Session id (must be active).
+    #[arg(long)]
+    pub session: String,
+
+    /// New Agent Window outer width in CSS pixels (100..=7680).
+    #[arg(long, value_parser = window_size)]
+    pub width: u32,
+
+    /// New Agent Window outer height in CSS pixels (100..=7680).
+    #[arg(long, value_parser = window_size)]
+    pub height: u32,
+}
+
+/// Parse a `--width` / `--height` Agent Window dimension (CSS pixels).
+fn window_size(s: &str) -> Result<u32, String> {
+    let value: u32 = s
+        .parse()
+        .map_err(|_| format!("invalid window dimension {s:?}: expected a positive integer"))?;
+    if (100..=7680).contains(&value) {
+        Ok(value)
+    } else {
+        Err(format!(
+            "window dimension {value} out of range (100..=7680)"
+        ))
+    }
+}
+
+pub fn dispatch(cmd: WindowCmd, format: Format) -> Result<(), CliError> {
+    let info = ensure_daemon().context("ensure daemon is running")?;
+    match cmd.sub {
+        WindowSub::Resize(args) => run_resize(info.sock_path, args, format),
+    }
+}
+
+fn run_resize(sock: PathBuf, args: WindowResizeArgs, format: Format) -> Result<(), CliError> {
+    let params = WindowResizeParams {
+        session_id: args.session,
+        width: args.width,
+        height: args.height,
+    };
+    let reply: WindowResizeResult =
+        ipc_call("window-resize-1", Method::ToolWindowResize, sock, params)?;
+    match format {
+        Format::Json => {
+            let json = serde_json::to_string_pretty(&reply)
+                .map_err(|e| CliError::Local(anyhow::anyhow!(e)))?;
+            println!("{json}");
+        }
+        Format::Human => {
+            println!(
+                "resized window_id={} to {}x{}",
+                reply.window_id, reply.width, reply.height
+            );
+        }
+    }
+    Ok(())
+}
+
+fn ipc_call<P, R>(
+    rpc_id_prefix: &'static str,
+    method: Method,
+    sock: PathBuf,
+    params: P,
+) -> Result<R, CliError>
+where
+    P: serde::Serialize + Send + 'static,
+    R: serde::de::DeserializeOwned + Send + 'static,
+{
+    crate::cli::business_rpc::call::<P, R>(
+        sock,
+        rpc_id_prefix,
+        method,
+        Some(params),
+        TOOL_IPC_TIMEOUT,
+    )
+}