fix(tui): re-exec with package tsconfig when cwd cannot compile solid jsx

[LeXwDeX]

Closes #465

Why

Source-mode boots of the CLI (e.g. bun --conditions=browser packages/opencode/src/index.ts) crash from any directory without a compatible tsconfig.json:

Unexpected error
Cannot find package 'react' imported from packages/tui/src/config/index.tsx

Root cause: Bun snapshots JSX transpiler settings from $cwd/tsconfig.json at startup. When the cwd has none (or one without @opentui/solid as jsxImportSource), every TUI .tsx file is compiled against the react runtime, and resolution of react/jsx-dev-runtime fails — react is not installed anywhere in this monorepo. The whole TUI graph is affected (app.tsx, config/index.tsx, …), not a single file. Reproduced identically on main; not introduced by the upstream sync.

What changed

• packages/opencode/src/cli/cmd/tui.ts: before entering the TUI flow, detect the hostile-transpile condition (source mode + cwd tsconfig missing or lacking @opentui/solid) and re-exec the same entry from the package directory, which owns a compatible tsconfig. process.execArgv is preserved (--conditions=browser etc. survive), and the original directory keeps reaching thread/worker resolution through the existing [project] positional + process.chdir path — project keys stay on the user's directory.
• Compiled binaries are unaffected and skip the guard (the candidate tsconfig only exists in a source checkout; binaries embed pre-compiled code).
• The re-exec is loop-proof: the child boots with the package tsconfig in cwd, so the guard no-ops.

Evidence

• Hostile cwd (fixture project, no tsconfig) + pty: before = crash in ~2s with react resolution error; after = TUI alive at 20s with real render output (ANSI frames, provider labels), zero errors.
• Normal path untouched: bun run dev -- --version from packages/opencode does not re-exec (tsconfig present).
• bun typecheck PASS; test/cli/cmd/tui/ 18 pass / 0 fail.
• Non-TUI commands (serve, models) never load the TUI graph and never hit the guard.