Migrate to per-agent subdirectories, uniform 8-agent support, cross-platform fixes

- All paths use ~/.elydora/{agentId}/ per-agent isolation
- Add copilot, letta plugins; split kiro into kirocli + kiroide
- Remove augment (SDK-only agent, not one-click)
- Fix guard command: use sys.executable instead of hardcoded python3
- Fix chmod wrapped in try/except for Windows compatibility
- Fix OpenCode chain state: save after HTTP 2xx response
- Fix guard script shebang consistency (sys.executable)
- Uniform 8 agents: claudecode, cursor, gemini, kirocli, kiroide, opencode, copilot, letta

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

elydora/plugins/base.py

@@ -15,6 +15,7 @@ else:
 class InstallConfig(TypedDict, total=False):
     org_id: str
     agent_id: str
+    agent_name: str
     private_key: str
     kid: str
     token: str
@@ -36,7 +37,7 @@ class AgentPlugin(ABC):
         """Install the Elydora hook for this agent."""
 
     @abstractmethod
-    def uninstall(self) -> None:
+    def uninstall(self, agent_id: str = "") -> None:
         """Remove the Elydora hook for this agent."""
 
     @abstractmethod