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
+}

packages/tfcode/src/control-plane/adaptors/worktree.ts

@@ -0,0 +1,46 @@
+import z from "zod"
+import { Worktree } from "@/worktree"
+import { type Adaptor, WorkspaceInfo } from "../types"
+
+const Config = WorkspaceInfo.extend({
+  name: WorkspaceInfo.shape.name.unwrap(),
+  branch: WorkspaceInfo.shape.branch.unwrap(),
+  directory: WorkspaceInfo.shape.directory.unwrap(),
+})
+
+type Config = z.infer<typeof Config>
+
+export const WorktreeAdaptor: Adaptor = {
+  async configure(info) {
+    const worktree = await Worktree.makeWorktreeInfo(info.name ?? undefined)
+    return {
+      ...info,
+      name: worktree.name,
+      branch: worktree.branch,
+      directory: worktree.directory,
+    }
+  },
+  async create(info) {
+    const config = Config.parse(info)
+    const bootstrap = await Worktree.createFromInfo({
+      name: config.name,
+      directory: config.directory,
+      branch: config.branch,
+    })
+    return bootstrap()
+  },
+  async remove(info) {
+    const config = Config.parse(info)
+    await Worktree.remove({ directory: config.directory })
+  },
+  async fetch(info, input: RequestInfo | URL, init?: RequestInit) {
+    const config = Config.parse(info)
+    const { WorkspaceServer } = await import("../workspace-server/server")
+    const url = input instanceof Request || input instanceof URL ? input : new URL(input, "http://opencode.internal")
+    const headers = new Headers(init?.headers ?? (input instanceof Request ? input.headers : undefined))
+    headers.set("x-opencode-directory", config.directory)
+
+    const request = new Request(url, { ...init, headers })
+    return WorkspaceServer.App().fetch(request)
+  },
+}