fix(terminal): create PTYs at the client viewport size, not 80x24 (#2023)

New terminals were always spawned by the daemon at the hardcoded 80x24
default and only resized once the client's first resize arrived. On a
slow first mount that leaves a window -- or a stuck state -- where a new
terminal renders far smaller than its pane (e.g. vim in a corner).

Seed the PTY with the client's measured viewport size at creation time
so it is born at the right size and the race window is gone.

- protocol: optional `size` on create_terminal_request. Old daemons
  ignore it and keep 80x24; old clients send nothing. Fully backward
  compatible, no capability gate.
- client: a small last-measured-size cache keyed by serverId+cwd (every
  terminal in a workspace shares the pane) with a most-recent fallback;
  written on fit, read at create.
- server: thread rows/cols through the controller, terminal manager, and
  the worker-thread boundary into the existing size-aware createTerminal.

Tests: cache logic, protocol back-compat parse, controller forwarding.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

packages/server/src/terminal/terminal-manager.ts

@@ -60,6 +60,8 @@ export interface TerminalManager {
     env?: Record<string, string>;
     command?: string;
     args?: string[];
+    rows?: number;
+    cols?: number;
     activityToken?: string;
     activityUrl?: string | null;
   }): Promise<TerminalSession>;
@@ -315,6 +317,8 @@ export function createTerminalManager(
       env?: Record<string, string>;
       command?: string;
       args?: string[];
+      rows?: number;
+      cols?: number;
       activityToken?: string;
       activityUrl?: string | null;
     }): Promise<TerminalSession> {
@@ -348,6 +352,8 @@ export function createTerminalManager(
             ...(options.title ? { title: options.title } : {}),
             ...(options.command ? { command: options.command } : {}),
             ...(options.args ? { args: options.args } : {}),
+            ...(options.rows !== undefined ? { rows: options.rows } : {}),
+            ...(options.cols !== undefined ? { cols: options.cols } : {}),
             ...(mergedEnv ? { env: mergedEnv } : {}),
             activityEnv,
           }),