feat: Anthropic web server tools, provider metadata, messaging hardening

- Add local web_search/web_fetch SSE handling and optional tool schemas
- Extend HeuristicToolParser for JSON-style WebFetch/WebSearch text
- Consolidate provider defaults, ids, and exception typing; stream contracts
- Messaging: typed options, voice config injection, platform contract cleanup
- Tests for web server tools, converters, parsers, contracts; ignore debug-*.log

config/provider_ids.py

@@ -0,0 +1,17 @@
+"""Canonical list of model provider type prefixes (provider_id values).
+
+`providers.registry.PROVIDER_DESCRIPTORS` is the full metadata source; this
+module holds the id set for config validation and must stay in sync
+(registries assert in `providers.registry`).
+"""
+
+from __future__ import annotations
+
+# Order matches docs / historical error text; must match PROVIDER_DESCRIPTORS keys.
+SUPPORTED_PROVIDER_IDS: tuple[str, ...] = (
+    "nvidia_nim",
+    "open_router",
+    "deepseek",
+    "lmstudio",
+    "llamacpp",
+)