Tiingo WebSocket streaming: re-enable the level-breach monitor

The monitor has been dead since the Oanda feed switch (Oanda's provider
does not stream). New config.json scalar data_providers.streaming selects
a tick-stream provider independent of the candle feed; telegram_bot
resolves it via _get_streaming_dp() (separate instance, candle cache
stays on the active provider) and falls back to the active provider when
unset — behavior is byte-identical to before when the key is absent.

TiingoDataProvider grows the two sanctioned streaming overrides:
supports_streaming=True and iter_ticks() on wss://api.tiingo.com/fx
(mid price only — the no-spread rule extends to the stream). Two
deliberate divergences from the TD reference implementation, both
because Tiingo authenticates inside the socket: server "E" messages
raise TiingoDataError (a swallowed auth error would end the generator
cleanly and reconnect-hammer with zero backoff), and on_connect fires on
the first received message rather than after the subscribe send. Field
order of quote frames was live-verified: ask is data[7], not data[6] as
the docs table suggests (data[6] is askSize).

make_data_provider(config, name=None) now takes an explicit provider
name; keyless streaming providers disable the monitor with one warning
instead of a traceback-per-minute loop.

Tests 266 → 273 (WS parser, ticker round-trip, streaming config scalar,
explicit-name dispatch, streaming-dp resolution, monitor auto-disable).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nsd8HcrV67GbCZXxZEn1Ma

providers/__init__.py

@@ -6,12 +6,13 @@ caching, validation, boundary guarantees, and range pagination — the
 behavior the signal pipeline depends on).
 
 Adding a provider = one module implementing `_fetch_raw` + one registry
-entry + one config.json `data_providers` block. The live feed is selected
-by config.json `data_providers.active`; registration alone changes
-nothing.
+entry + one config.json `data_providers` block. The live candle feed is
+selected by config.json `data_providers.active`; the optional
+`data_providers.streaming` scalar selects a different provider for the
+tick stream (level-breach monitor). Registration alone changes nothing.
 """
 
-from typing import Dict
+from typing import Dict, Optional
 
 from app_config import AppConfigError, get_app_config
 from config import PlatformConfig
@@ -29,9 +30,11 @@ PROVIDER_REGISTRY: Dict[str, type] = {
 }
 
 
-def make_data_provider(config: PlatformConfig) -> BaseDataProvider:
-    """Build the ACTIVE data provider (config.json: data_providers.active)."""
-    name = get_app_config().active_provider
+def make_data_provider(config: PlatformConfig,
+                       name: Optional[str] = None) -> BaseDataProvider:
+    """Build a provider by name (default: config.json data_providers.active)."""
+    if name is None:
+        name = get_app_config().active_provider
     cls = PROVIDER_REGISTRY.get(name)
     if cls is None:
         raise AppConfigError(