fix(opencode): register solid transform from any cwd - #40230

Issue for this PR

Closes #40231

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Running opencode from source (bun run packages/opencode/src/index.ts) from any directory outside the repo shows a black screen and never mounts.

The TUI uses the Solid JSX transform from @opentui/solid, applied by a Bun plugin that is only registered when the CWD's bunfig.toml chain contains preload = ["@opentui/solid/preload"] — which only exists inside the repo. From any other directory Bun falls back to its default React-style JSX transform, emitting element objects opentui's reconciler cannot mount: App never runs, nothing draws, and ctrl-c is unresponsive.

This registers the transform at the process entrypoint (import "@opentui/solid/preload" as the first import in packages/opencode/src/index.ts), decoupling plugin registration from ambient bunfig.toml. ensureSolidTransformPlugin() is idempotent (global installed flag), so it is a no-op when already registered and is inert in compiled binaries, which bundle the transform at build time (compile: { autoloadBunfig: false }).

How did you verify your code works?

• Ran the TUI from /tmp/ocdevtest (outside the repo) with bun run --conditions=browser packages/opencode/src/index.ts: without the fix the screen stays black; with the fix the full dashboard renders (logo, model selector, tabs, status bar) and render/sync/theme bootstrap resolve. Verified on bun 1.3.14 and reproduced the bug on the same version without the fix.
• Confirmed output matches a run from inside the repo.
• bun typecheck passes for the opencode package.

Screenshots / recordings

Not applicable; verified via a pty harness.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR