feat(chat): make streaming and chat timeouts per-profile configurable

The chat request previously used a hard-coded 30 s timeout and ignored
--read-timeout entirely (that flag only bounded URL prompt fetching), so
slow reasoning models were cut off mid-generation unless one remembered
to pass --stream (which used a separate hard-coded 600 s).

Resolve `stream`, `read_timeout` and `connect_timeout` from
[default]/[model.<profile>] into PromptConfig and wire the (connect, read)
timeout into both the streaming and non-streaming chat calls. CLI
--stream/--read-timeout/--connect-timeout still override; the two timeout
flags default to None so a config value can win, with the URL-fetch
fallbacks (3 s/10 s) preserved. Default chat read_timeout is now 600 s.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_config.py

@@ -258,3 +258,33 @@ def test_chat_params_cli_overrides_config(tmp_path):
     _, prompt_cfg = resolve_effective_config(args)
     assert prompt_cfg.max_tokens == 512
     assert prompt_cfg.temperature == 0.1
+
+
+def test_stream_and_timeouts_default(tmp_path):
+    cfg_path = _write_config(tmp_path)
+    _, prompt_cfg = resolve_effective_config(_parse(["--start", "--config", str(cfg_path)]))
+    assert prompt_cfg.stream is False
+    assert prompt_cfg.read_timeout == 600.0  # generous default for reasoning models
+    assert prompt_cfg.connect_timeout == 10.0
+
+
+def test_stream_and_read_timeout_from_config(tmp_path):
+    cfg = CONFIG_BASIC.replace(
+        "poll_interval = 2",
+        "poll_interval = 2\nstream = true\nread_timeout = 900\nconnect_timeout = 5",
+    )
+    cfg_path = _write_config(tmp_path, cfg)
+    _, prompt_cfg = resolve_effective_config(_parse(["--start", "--config", str(cfg_path)]))
+    assert prompt_cfg.stream is True
+    assert prompt_cfg.read_timeout == 900.0
+    assert prompt_cfg.connect_timeout == 5.0
+
+
+def test_stream_and_read_timeout_cli_overrides_config(tmp_path):
+    cfg = CONFIG_BASIC.replace("poll_interval = 2", "poll_interval = 2\nread_timeout = 900")
+    cfg_path = _write_config(tmp_path, cfg)
+    # --stream forces streaming on; --read-timeout overrides the config value.
+    args = _parse(["--chat", "-p", "hi", "--config", str(cfg_path), "--stream", "--read-timeout", "42"])
+    _, prompt_cfg = resolve_effective_config(args)
+    assert prompt_cfg.stream is True
+    assert prompt_cfg.read_timeout == 42.0