fix(schema): restore lost changes from cherry-pick conflict resolution

- Restore enable attribute to ExecToolConfig
- Remove deprecated memory_window field (was removed in f44c4f9 but brought back by cherry-pick)
- Restore exclude=True on openai_codex and github_copilot oauth providers

nanobot/config/schema.py

@@ -38,15 +38,8 @@ class AgentDefaults(Base):
     context_window_tokens: int = 65_536
     temperature: float = 0.1
     max_tool_iterations: int = 40
-    # Deprecated compatibility field: accepted from old configs but ignored at runtime.
-    memory_window: int | None = Field(default=None, exclude=True)
     reasoning_effort: str | None = None  # low / medium / high — enables LLM thinking mode
 
-    @property
-    def should_warn_deprecated_memory_window(self) -> bool:
-        """Return True when old memoryWindow is present without contextWindowTokens."""
-        return self.memory_window is not None and "context_window_tokens" not in self.model_fields_set
-
 
 class AgentsConfig(Base):
     """Agent configuration."""
@@ -86,8 +79,8 @@ class ProvidersConfig(Base):
     volcengine_coding_plan: ProviderConfig = Field(default_factory=ProviderConfig)  # VolcEngine Coding Plan
     byteplus: ProviderConfig = Field(default_factory=ProviderConfig)  # BytePlus (VolcEngine international)
     byteplus_coding_plan: ProviderConfig = Field(default_factory=ProviderConfig)  # BytePlus Coding Plan
-    openai_codex: ProviderConfig = Field(default_factory=ProviderConfig)  # OpenAI Codex (OAuth)
-    github_copilot: ProviderConfig = Field(default_factory=ProviderConfig)  # Github Copilot (OAuth)
+    openai_codex: ProviderConfig = Field(default_factory=ProviderConfig, exclude=True)  # OpenAI Codex (OAuth)
+    github_copilot: ProviderConfig = Field(default_factory=ProviderConfig, exclude=True)  # Github Copilot (OAuth)
 
 
 class HeartbeatConfig(Base):
@@ -126,6 +119,7 @@ class WebToolsConfig(Base):
 class ExecToolConfig(Base):
     """Shell exec tool configuration."""
 
+    enable: bool = True
     timeout: int = 60
     path_append: str = ""