# Title

Theme change interrupts/kills running opencode sessions (`omarchy-restart-opencode` broadcasts SIGUSR2)

# Body

## Summary

Every `omarchy theme set <name>` runs `omarchy-restart-opencode`, which does a blanket
`killall -SIGUSR2 opencode` across all opencode processes. Any opencode process without a
SIGUSR2 handler terminates (default signal disposition), and even interactive TUI sessions
take a forced config reload that aborts in-flight generation. Changing theme while opencode
is working interrupts it — unlike Claude Code on the same system, which omarchy retints
passively via a watched file.

## System details

- Omarchy: 4.0.0.r1816.g43bfe9b-1
- Kernel: 7.1.9-arch1-2
- CPU: 12th Gen Intel(R) Core(TM) i5-12450HX
- GPU: Intel Alder Lake-S UHD Graphics
- opencode: 1.18.21 (via mise)

## Version

Omarchy 4.0.0.r1816.g43bfe9b-1 (Arch Linux, Hyprland)

## Root cause

- `bin/omarchy-theme-set` includes `omarchy-restart-opencode` in `post_theme_commands`
  and runs it on every theme apply.
- `bin/omarchy-restart-opencode` = `pgrep -x opencode && killall -SIGUSR2 opencode`.
- In opencode (verified against v1.18.x binaries), only the interactive TUI registers
  SIGUSR2 handlers (config reload + rescan of `~/.config/opencode/themes/*.json`).
  Headless processes — `opencode run`, servers, spawned agents — have no handler and are
  killed by the default disposition.
- Notably, omarchy ships no generated theme artifact for opencode at all (no opencode
  template under `default/themed/`, nothing in stock themes). So the signal delivers no
  Omarchy colors; unless a user maintains their own `~/.config/opencode/themes/*.json`,
  this call has no upside and only interrupts running work.

## Reproduction

1. Start a task that takes a while: `opencode run "Write the numbers from 1 to 80, one per line"`
2. While it is mid-run, from another terminal: `omarchy theme set <any-theme>`
3. The run dies immediately.

Targeted-signal confirmation of what the broadcast does:

```
$ opencode run "Write the numbers from 1 to 80, one per line" &
$ kill -USR2 <pid>          # exactly what omarchy-restart-opencode does
User defined signal 2       exit code 140 (128+SIGUSR2), task produced nothing
```

Interactive TUI sessions survive the signal itself but get their active generation
interrupted by the forced server reload.

For comparison: `omarchy-theme-set-claude` writes `~/.claude/themes/omarchy.json`, which
Claude Code hot-reloads by file watch — running sessions retint without any signal.
Codex isn't signaled at all. Only opencode gets the kill-the-process treatment.

## Expected

Changing themes should not terminate or disrupt running coding-agent sessions.

## Suggested fix

Drop `omarchy-restart-opencode` from `post_theme_commands` in `bin/omarchy-theme-set`.
Since omarchy generates no opencode theme data today, removing it changes no visual
behavior. If opencode integration is wanted later, the Claude pattern is the model:
generate a theme file opencode can pick up passively rather than signaling processes.

## Notes

- PR #4566 touched this same script but only silenced the "no process found" error.
- Local stopgap for affected users: shadow `omarchy-restart-opencode` with a no-op
  earlier in PATH (e.g. via a prepended dir in `~/.bash_profile`, since
  `post_theme_commands` run through `bash -lc`).

## Attachments

- Full repro transcript and exit codes available on request (captured locally).