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/file/path-traversal.test.ts

@@ -0,0 +1,198 @@
+import { test, expect, describe } from "bun:test"
+import path from "path"
+import fs from "fs/promises"
+import { Filesystem } from "../../src/util/filesystem"
+import { File } from "../../src/file"
+import { Instance } from "../../src/project/instance"
+import { tmpdir } from "../fixture/fixture"
+
+describe("Filesystem.contains", () => {
+  test("allows paths within project", () => {
+    expect(Filesystem.contains("/project", "/project/src")).toBe(true)
+    expect(Filesystem.contains("/project", "/project/src/file.ts")).toBe(true)
+    expect(Filesystem.contains("/project", "/project")).toBe(true)
+  })
+
+  test("blocks ../ traversal", () => {
+    expect(Filesystem.contains("/project", "/project/../etc")).toBe(false)
+    expect(Filesystem.contains("/project", "/project/src/../../etc")).toBe(false)
+    expect(Filesystem.contains("/project", "/etc/passwd")).toBe(false)
+  })
+
+  test("blocks absolute paths outside project", () => {
+    expect(Filesystem.contains("/project", "/etc/passwd")).toBe(false)
+    expect(Filesystem.contains("/project", "/tmp/file")).toBe(false)
+    expect(Filesystem.contains("/home/user/project", "/home/user/other")).toBe(false)
+  })
+
+  test("handles prefix collision edge cases", () => {
+    expect(Filesystem.contains("/project", "/project-other/file")).toBe(false)
+    expect(Filesystem.contains("/project", "/projectfile")).toBe(false)
+  })
+})
+
+/*
+ * Integration tests for File.read() and File.list() path traversal protection.
+ *
+ * These tests verify the HTTP API code path is protected. The HTTP endpoints
+ * in server.ts (GET /file/content, GET /file) call File.read()/File.list()
+ * directly - they do NOT go through ReadTool or the agent permission layer.
+ *
+ * This is a SEPARATE code path from ReadTool, which has its own checks.
+ */
+describe("File.read path traversal protection", () => {
+  test("rejects ../ traversal attempting to read /etc/passwd", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        await Bun.write(path.join(dir, "allowed.txt"), "allowed content")
+      },
+    })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        await expect(File.read("../../../etc/passwd")).rejects.toThrow("Access denied: path escapes project directory")
+      },
+    })
+  })
+
+  test("rejects deeply nested traversal", async () => {
+    await using tmp = await tmpdir()
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        await expect(File.read("src/nested/../../../../../../../etc/passwd")).rejects.toThrow(
+          "Access denied: path escapes project directory",
+        )
+      },
+    })
+  })
+
+  test("allows valid paths within project", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        await Bun.write(path.join(dir, "valid.txt"), "valid content")
+      },
+    })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const result = await File.read("valid.txt")
+        expect(result.content).toBe("valid content")
+      },
+    })
+  })
+})
+
+describe("File.list path traversal protection", () => {
+  test("rejects ../ traversal attempting to list /etc", async () => {
+    await using tmp = await tmpdir()
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        await expect(File.list("../../../etc")).rejects.toThrow("Access denied: path escapes project directory")
+      },
+    })
+  })
+
+  test("allows valid subdirectory listing", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        await Bun.write(path.join(dir, "subdir", "file.txt"), "content")
+      },
+    })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const result = await File.list("subdir")
+        expect(Array.isArray(result)).toBe(true)
+      },
+    })
+  })
+})
+
+describe("Instance.containsPath", () => {
+  test("returns true for path inside directory", async () => {
+    await using tmp = await tmpdir({ git: true })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: () => {
+        expect(Instance.containsPath(path.join(tmp.path, "foo.txt"))).toBe(true)
+        expect(Instance.containsPath(path.join(tmp.path, "src", "file.ts"))).toBe(true)
+      },
+    })
+  })
+
+  test("returns true for path inside worktree but outside directory (monorepo subdirectory scenario)", async () => {
+    await using tmp = await tmpdir({ git: true })
+    const subdir = path.join(tmp.path, "packages", "lib")
+    await fs.mkdir(subdir, { recursive: true })
+
+    await Instance.provide({
+      directory: subdir,
+      fn: () => {
+        // .opencode at worktree root, but we're running from packages/lib
+        expect(Instance.containsPath(path.join(tmp.path, ".opencode", "state"))).toBe(true)
+        // sibling package should also be accessible
+        expect(Instance.containsPath(path.join(tmp.path, "packages", "other", "file.ts"))).toBe(true)
+        // worktree root itself
+        expect(Instance.containsPath(tmp.path)).toBe(true)
+      },
+    })
+  })
+
+  test("returns false for path outside both directory and worktree", async () => {
+    await using tmp = await tmpdir({ git: true })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: () => {
+        expect(Instance.containsPath("/etc/passwd")).toBe(false)
+        expect(Instance.containsPath("/tmp/other-project")).toBe(false)
+      },
+    })
+  })
+
+  test("returns false for path with .. escaping worktree", async () => {
+    await using tmp = await tmpdir({ git: true })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: () => {
+        expect(Instance.containsPath(path.join(tmp.path, "..", "escape.txt"))).toBe(false)
+      },
+    })
+  })
+
+  test("handles directory === worktree (running from repo root)", async () => {
+    await using tmp = await tmpdir({ git: true })
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: () => {
+        expect(Instance.directory).toBe(Instance.worktree)
+        expect(Instance.containsPath(path.join(tmp.path, "file.txt"))).toBe(true)
+        expect(Instance.containsPath("/etc/passwd")).toBe(false)
+      },
+    })
+  })
+
+  test("non-git project does not allow arbitrary paths via worktree='/'", async () => {
+    await using tmp = await tmpdir() // no git: true
+
+    await Instance.provide({
+      directory: tmp.path,
+      fn: () => {
+        // worktree is "/" for non-git projects, but containsPath should NOT allow all paths
+        expect(Instance.containsPath(path.join(tmp.path, "file.txt"))).toBe(true)
+        expect(Instance.containsPath("/etc/passwd")).toBe(false)
+        expect(Instance.containsPath("/tmp/other")).toBe(false)
+      },
+    })
+  })
+})