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/control-plane/adaptors/index.ts

@@ -0,0 +1,20 @@
+import { lazy } from "@/util/lazy"
+import type { Adaptor } from "../types"
+
+const ADAPTORS: Record<string, () => Promise<Adaptor>> = {
+  worktree: lazy(async () => (await import("./worktree")).WorktreeAdaptor),
+}
+
+export function getAdaptor(type: string): Promise<Adaptor> {
+  return ADAPTORS[type]()
+}
+
+export function installAdaptor(type: string, adaptor: Adaptor) {
+  // This is experimental: mostly used for testing right now, but we
+  // will likely allow this in the future. Need to figure out the
+  // TypeScript story
+
+  // @ts-expect-error we force the builtin types right now, but we
+  // will implement a way to extend the types for custom adaptors
+  ADAPTORS[type] = () => adaptor
+}