refactor: drop --cd and simplify config lookup

readme.md

@@ -46,8 +46,6 @@ chat_id = 123456789
 
 The bridge only accepts messages where the chat ID equals the sender ID and both match `chat_id` (i.e., private chat with that user).
 
-When you pass `--cd`, Takopi looks for `.codex/takopi.toml` under that directory first.
-
 ### Codex Profile (Optional)
 
 Create a Codex profile in `~/.codex/config.toml`:
@@ -75,7 +73,6 @@ uv run takopi
 |------|---------|-------------|
 | `--final-notify` / `--no-final-notify` | `--final-notify` | Send final response as new message (vs. edit) |
 | `--debug` / `--no-debug` | `--no-debug` | Enable verbose logging |
-| `--cd PATH` | cwd | Working directory for Codex |
 | `--profile NAME` | (codex default) | Codex profile name |
 
 ## Usage