Make the read-only agent terminal mirrors stream in real time and give
the agent a desktop-only way to dismiss its own tabs.
- Stream background output live: the local reader used a blocking
read(4096) that buffered small periodic output until EOF, so agent
tabs only "filled in" at process exit. Switch to buffer.read1(4096)
(decoded) for incremental chunks.
- Route agent.terminal.output / terminal.close to the window that owns
the process (its gateway session) instead of an empty session id, so
events actually reach the desktop renderer.
- Add close_terminal: a HERMES_DESKTOP-gated tool (sibling of
read_terminal) that drops a process's read-only tab WITHOUT killing it
via process_registry.on_close; output keeps buffering and the user can
reopen from the status stack.
- ⌘W now closes a focused agent tab: mark the agent instance
data-terminal and focus it on activation so isFocusWithin routes there.
- ensureTerminal() no longer spawns an extra user shell when a tab
already exists (e.g. opening a background task from the status stack).
