feat: add initial socket api for workspace and pane control

add unix socket request/response api scaffolding

implement initial workspace and pane commands:
- ping
- workspace.list
- workspace.get
- workspace.create
- pane.list
- pane.get
- pane.read
- pane.send_text
- pane.send_keys
- pane.wait_for_output

improve pane read semantics:
- visible trims trailing blank viewport rows
- recent reads from parser scrollback/current screen
- wait_for_output returns matched snapshot plus matched_line

add real subprocess integration tests for socket api

1 files changed, 1 insertions, 0 deletions

diff --git a/Cargo.lock b/Cargo.lock
index aa88d227..7f4fe64f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -459,6 +459,7 @@ dependencies = [
  "libc",
  "portable-pty",
  "ratatui",
+ "regex",
  "serde",
  "serde_json",
  "tokio",