refactor: apply minimal tfcode branding

- Rename packages/opencode → packages/tfcode (directory only)
- Rename bin/opencode → bin/tfcode (CLI binary)
- Rename .opencode → .tfcode (config directory)
- Update package.json name and bin field
- Update config directory path references (.tfcode)
- Keep internal code references as 'opencode' for easy upstream sync
- Keep @opencode-ai/* workspace package names

This minimal branding approach allows clean merges from upstream
opencode repository while providing tfcode branding for users.

packages/tfcode/src/effect/run-service.ts

@@ -0,0 +1,13 @@
+import { Effect, Layer, ManagedRuntime } from "effect"
+import * as ServiceMap from "effect/ServiceMap"
+
+export const memoMap = Layer.makeMemoMapUnsafe()
+
+export function makeRunPromise<I, S, E>(service: ServiceMap.Service<I, S>, layer: Layer.Layer<I, E>) {
+  let rt: ManagedRuntime.ManagedRuntime<I, E> | undefined
+
+  return <A, Err>(fn: (svc: S) => Effect.Effect<A, Err, I>, options?: Effect.RunOptions) => {
+    rt ??= ManagedRuntime.make(layer, { memoMap })
+    return rt.runPromise(service.use(fn), options)
+  }
+}