Module session 

Session manager — owns and manages active shell sessions.

SessionManager is the core lifecycle engine for interactive PTY sessions. It provides thread-safe creation, I/O, and cleanup of ShellSessions, each backed by a PtyHandle and a ReadinessDetector.

Design invariants:

• The Mutex is held only for HashMap insert/remove — never during I/O.
• Sessions are removed from the map before I/O and reinserted after, so the lock is never contended by blocking reads/writes.
• ANSI escape sequences are stripped from all output before returning.

Structs

SendResult

Result of sending input to a session.

SessionManager

Thread-safe manager for all active shell sessions.

SessionOpts

Options for creating a new session.

ShellSessionInfo

Snapshot of session metadata (no mutable borrows needed).

Enums

SessionStatus

Lifecycle status of a session.

Functions

start_reaper

Spawn a background task that periodically reaps idle sessions.