Clear TODO backlog: --debug/--profile, codex selection, MCP orientation, perf

- Add --debug[=DIR] / --profile[=DIR] flags that write run artefacts
  (patterm.log, events.jsonl, per-child raw PTY captures, CPU + heap
  + goroutine pprof) to a dir without polluting stdout/stderr.
- Strengthen vendor-TUI orientation in three places (MCP
  initialize.instructions, the spawn_agent tool description, and
  help('spawning')) to head off codex's habits of poking the Unix
  socket via perl and shelling out to launch peers — both bypass
  caller identity and produce orphaned top-level tabs.
- Fix click-and-drag text selection from alt-screen TUIs. Host SGR
  mouse reporting now follows the focused child's screen side
  instead of being permanently armed; alt-screen TUIs that need
  mouse re-enable it themselves and the toggle is forwarded.
- Move drawSidebar() off the per-PTY-chunk hot path. Long claude
  session resume was paying a full sidebar rebuild for every
  scrolled chunk; the chrome ticker now drains a dirty flag at 60 Hz.
- Gate the per-chunk Title() CGO poll on a containsOSC scan so
  codex/ratatui's many SGR-only chunks no longer pay a CGO call each.

TODO.md

@@ -1,15 +1,3 @@
-- [ ] Codex seemed to think that it needed to launch patterm itself to get the mcp working
-- [ ] I cant click and drag to select text from codex
-- [ ] codex uses perl to interact with the socket rather than calling mcp tools
-  - when it _did_ open a sub claude it opened it as a separate tab rather than a sub-agent.
-- [ ] codex rendering is VERY slow
-  - maybe we need to use diffing rather than rendering the entire viewport for performance
-- We should add a --debug and --profile flag, so we can get detailed performance data and full logs of the agent output to be debugged later on.
-  - I don't mind what format this is in, ideally easy for LLMs to understand
-- [ ] Resuming a long claude session takes a couple of seconds for the entire buffer to load in, it looks like it's scrolling down for a couple seconds.
-  - In raw alacritty this is instant, so there's some sort of performance issue with patterm's terminal emulation.
-
-
 # On Hold
 - [ ] There's a unicode <?> being displayed in opencode [ON HOLD]
   - Investigated 2026-05-14: patterm passes ghostty grapheme codepoints