Add chat-friendly shell read rendering

Make workspace shell reads usable as direct chat-model input without changing the PTY or cursor model. This adds optional plain rendering and idle-window batching across CLI, SDK, and MCP while keeping raw reads backward-compatible.

Implement the rendering and wait-for-idle logic in the manager layer so the existing guest/backend shell transport stays unchanged. The new helper strips ANSI and other terminal control noise, handles carriage-return overwrite and backspace, and preserves raw cursor semantics even when plain output is requested.

Refresh the stable shell docs/examples to recommend --plain --wait-for-idle-ms 300, mark the 3.5.0 roadmap milestone done, and bump the package/catalog version to 3.5.0.

Validation: uv lock; UV_CACHE_DIR=.uv-cache make check; UV_CACHE_DIR=.uv-cache make dist-check; real guest-backed Firecracker smoke covering shell open/write/read with ANSI plus delayed output.

examples/python_shell.py

@@ -19,7 +19,13 @@ def main() -> None:
             pyro.write_shell(workspace_id, shell_id, input="pwd")
             deadline = time.time() + 5
             while True:
-                read = pyro.read_shell(workspace_id, shell_id, cursor=0)
+                read = pyro.read_shell(
+                    workspace_id,
+                    shell_id,
+                    cursor=0,
+                    plain=True,
+                    wait_for_idle_ms=300,
+                )
                 output = str(read["output"])
                 if "/workspace" in output or time.time() >= deadline:
                     print(output, end="")

examples/python_workspace.py

@@ -83,7 +83,13 @@ def main() -> None:
                 shell_id,
                 input='printf "%s\\n" "$API_TOKEN"',
             )
-            shell_output = pyro.read_shell(workspace_id, shell_id, cursor=0)
+            shell_output = pyro.read_shell(
+                workspace_id,
+                shell_id,
+                cursor=0,
+                plain=True,
+                wait_for_idle_ms=300,
+            )
             print(f"shell_output_len={len(shell_output['output'])}")
             pyro.close_shell(workspace_id, shell_id)
             pyro.start_service(