feat: add theme hot-reload functionality

[malhashemi]

Summary

Adds the ability to reload themes without restarting opencode. Provides multiple reload triggers to support different workflows:

Trigger	Use Case
/reload-theme command	Manual reload when needed
File watchers	Auto-reload on config/theme file edits
Window resize	Re-detect terminal colors for "system" theme
SIGUSR1/SIGUSR2	Integration point for external automation

Also makes "system" theme background transparent to support terminal opacity.

Changes

 theme.tsx | +178 Core: reloadTheme(), file watchers, signal handlers
app.tsx | -66/+9 Moved getTerminalBackgroundColor, added command
autocomplete.tsx | +5 Added /reload-theme slash command

Architecture

flowchart LR
subgraph Triggers
A[Command]
B[File change]
C[Resize]
D[Signal]
end
A & B & C & D --> E[reloadTheme]
E --> F[Re-query colors]
F --> G[Update store]
G --> H[UI re-renders]

Loading

Key Decisions

Why move getTerminalBackgroundColor to theme.tsx?
Needed by both initial detection (app.tsx) and reload (theme.tsx). Moving it eliminates duplication.

Why fs.watch() instead of @parcel/watcher?
Simpler API, no extra dependencies, sufficient for watching 2 files.

Why transparent background for "system" theme?
Allows terminal opacity/blur to show through while keeping panel/menu backgrounds solid.

Why SIGWINCH handler?
Event-driven color re-detection without polling. Only active for "system" theme.

Testing

# Command
/reload-theme
# File watcherecho'{"theme":"dracula"}'>~/.config/opencode/opencode.json
# Signal (Unix)kill -USR1 $(pgrep opencode)# Resize (system theme)# Change terminal colors, then resize window

Checklist

• Commands work (palette + slash)
• File watchers trigger reload
• Signal handlers work (Unix)
• Proper cleanup on unmount
• TypeScript passes
• Follows AGENTS.md style

Fixes#815

[arthur404dev]

Is this feature still being worked on? Hot reloading the theme would be a really nice functionality for theme switching!

[malhashemi]

@rekram1-node would you please review this PR and let me know if you have any changes.

[rekram1-node]

Instead of slash command can we do command panel?

Like reload themes or something?

Also you are using a watcher is it possible to 'hot reload' them since you are filewatching?

[rekram1-node]

/review

[rekram1-node]

If im not looking at something that u need, feel free to dm on discord or x

I get like 200 github notifications a day so Im doing my best to go through them but stuff will always sneak through

[github-actions]

lgtm

[arthur404dev]

Maybe can this be merged in?

There's even two more PRs trying to achieve this same achievable, but this one already have the lgtm

[github-actions]

Closing this pull request because it has had no updates for more than 60 days. If you plan to continue working on it, feel free to reopen or open a new PR.

[fsiraj]

Can this still be merged in? The repo has 1.7k PRs so guessing this slipped through the cracks.