runtime: dynamic import(path, { with: { type: "toml" } }) of a runtime file path must parse TOML like Bun (OpenCode legacy config migration) #10104

Parent: #10107. Related: #5230 (deferred dynamic import), Bun.TOML (js_bun_toml exists in crates/perry-runtime/src/bun_compat).

Problem

packages/opencode/src/config/config.ts:276-290:

const legacy = path.join(Global.Path.config, "config")        // ~/.config/opencode/config  (pre-JSON TOML config)
if (existsSync(legacy)) {
  yield* Effect.promise(() =>
    import(pathToFileURL(legacy).href, { with: { type: "toml" } })
      .then(async (mod) => { const { provider, model, ...rest } = mod.default; … write config.json; unlink(legacy) })
      .catch(() => {}))
}

Bun parses the TOML file and returns { default: <object> }. Under perry the specifier is a runtime value, so #5230 defers it to ERR_MODULE_NOT_FOUND; the .catch(() => {}) swallows it and a user's legacy config (provider/model/etc.) is silently never migrated — a behavioural divergence, not a crash.

Scope

• In the runtime dynamic-import fallback (js_module_dynamic_import_fallback, fix(runtime): closure-nested dynamic import() invisible to the resolver rejected with literal undefined — pi one-shot lost-rejection wall (#6660) #6665), honour the import attribute for runtime paths: type: "toml" → read file + Bun.TOML.parse → { default }; also "json" → JSON.parse, "text" → string, "file" → path string, for parity with Bun's loaders. Only for file:///absolute paths; keep the existing deferred error for code modules.
• Error shape on parse failure: reject with a SyntaxError like Bun.

Repro

Create ~/.config/opencode/config with provider = "anthropic"\nmodel = "claude-sonnet-4-5"\n, run opencode --version (any command that loads config) under bun and under the native binary; expect config.json written and the legacy file removed in both.

Acceptance

• Fixture: await import(pathToFileURL(tmp).href, { with: { type: "toml" } }) returns the parsed table in a compiled program; JSON/text/file variants covered.
• The OpenCode legacy-config migration produces the same config.json as bun.