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/test/cli/plugin-auth-picker.test.ts

@@ -0,0 +1,120 @@
+import { test, expect, describe } from "bun:test"
+import { resolvePluginProviders } from "../../src/cli/cmd/providers"
+import type { Hooks } from "@opencode-ai/plugin"
+
+function hookWithAuth(provider: string): Hooks {
+  return {
+    auth: {
+      provider,
+      methods: [],
+    },
+  }
+}
+
+function hookWithoutAuth(): Hooks {
+  return {}
+}
+
+describe("resolvePluginProviders", () => {
+  test("returns plugin providers not in models.dev", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("portkey")],
+      existingProviders: {},
+      disabled: new Set(),
+      providerNames: {},
+    })
+    expect(result).toEqual([{ id: "portkey", name: "portkey" }])
+  })
+
+  test("skips providers already in models.dev", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("anthropic")],
+      existingProviders: { anthropic: {} },
+      disabled: new Set(),
+      providerNames: {},
+    })
+    expect(result).toEqual([])
+  })
+
+  test("deduplicates across plugins", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("portkey"), hookWithAuth("portkey")],
+      existingProviders: {},
+      disabled: new Set(),
+      providerNames: {},
+    })
+    expect(result).toEqual([{ id: "portkey", name: "portkey" }])
+  })
+
+  test("respects disabled_providers", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("portkey")],
+      existingProviders: {},
+      disabled: new Set(["portkey"]),
+      providerNames: {},
+    })
+    expect(result).toEqual([])
+  })
+
+  test("respects enabled_providers when provider is absent", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("portkey")],
+      existingProviders: {},
+      disabled: new Set(),
+      enabled: new Set(["anthropic"]),
+      providerNames: {},
+    })
+    expect(result).toEqual([])
+  })
+
+  test("includes provider when in enabled set", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("portkey")],
+      existingProviders: {},
+      disabled: new Set(),
+      enabled: new Set(["portkey"]),
+      providerNames: {},
+    })
+    expect(result).toEqual([{ id: "portkey", name: "portkey" }])
+  })
+
+  test("resolves name from providerNames", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("portkey")],
+      existingProviders: {},
+      disabled: new Set(),
+      providerNames: { portkey: "Portkey AI" },
+    })
+    expect(result).toEqual([{ id: "portkey", name: "Portkey AI" }])
+  })
+
+  test("falls back to id when no name configured", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithAuth("portkey")],
+      existingProviders: {},
+      disabled: new Set(),
+      providerNames: {},
+    })
+    expect(result).toEqual([{ id: "portkey", name: "portkey" }])
+  })
+
+  test("skips hooks without auth", () => {
+    const result = resolvePluginProviders({
+      hooks: [hookWithoutAuth(), hookWithAuth("portkey"), hookWithoutAuth()],
+      existingProviders: {},
+      disabled: new Set(),
+      providerNames: {},
+    })
+    expect(result).toEqual([{ id: "portkey", name: "portkey" }])
+  })
+
+  test("returns empty for no hooks", () => {
+    const result = resolvePluginProviders({
+      hooks: [],
+      existingProviders: {},
+      disabled: new Set(),
+      providerNames: {},
+    })
+    expect(result).toEqual([])
+  })
+})