Revert "merge: tier2/phase2_4_5_call_site_completion_20260621 (parent + follow-up + Phase 6e analysis)"

This reverts commit f914b2bcd4, reversing
changes made to 7fef95cc87.

src/provider_state.py

@@ -1,69 +0,0 @@
-"""Per-provider history state for the AI client layer.
-
-Promotes 14 module globals in src/ai_client.py:
-- 7x `_<provider>_history: list[Metadata]` (anthropic/deepseek/minimax/qwen/grok/llama)
-- 7x `_<provider>_history_lock: threading.Lock`
-
-To a single `_PROVIDER_HISTORIES: dict[str, ProviderHistory]` keyed by
-provider name. Each `ProviderHistory` owns its own lock and message list;
-the cross-provider pattern is encapsulated behind a 4-method interface.
-
-SDK client holders (`_gemini_chat`, `_deepseek_client`, etc.) stay as
-module-level `Any` variables per Pattern 3 (heterogeneous SDK types,
-lazy-initialized). Only the homogeneous history aspect is unified.
-
-CONVENTION: 1-space indentation. NO COMMENTS.
-"""
-from __future__ import annotations
-
-import threading
-from dataclasses import dataclass, field
-
-from src.type_aliases import HistoryMessage, Metadata
-
-
-@dataclass
-class ProviderHistory:
- messages: list[HistoryMessage] = field(default_factory=list)
- lock: threading.Lock = field(default_factory=threading.Lock)
-
- def append(self, message: HistoryMessage) -> None:
-  with self.lock:
-   self.messages.append(message)
-
- def get_all(self) -> list[HistoryMessage]:
-  with self.lock:
-   return list(self.messages)
-
- def replace_all(self, messages: list[HistoryMessage]) -> None:
-  with self.lock:
-   self.messages = list(messages)
-
- def clear(self) -> None:
-  with self.lock:
-   self.messages = []
-
-
-_PROVIDER_HISTORIES: dict[str, ProviderHistory] = {
- "anthropic": ProviderHistory(),
- "deepseek": ProviderHistory(),
- "minimax": ProviderHistory(),
- "qwen": ProviderHistory(),
- "grok": ProviderHistory(),
- "llama": ProviderHistory(),
-}
-
-
-def get_history(provider: str) -> ProviderHistory:
- if provider not in _PROVIDER_HISTORIES:
-  raise KeyError(f"Unknown provider: {provider!r}")
- return _PROVIDER_HISTORIES[provider]
-
-
-def clear_all() -> None:
- for h in _PROVIDER_HISTORIES.values():
-  h.clear()
-
-
-def providers() -> tuple[str, ...]:
- return tuple(_PROVIDER_HISTORIES.keys())