Refactor subagent and workflow domain models; migrate access tiers and events to domain module

- Moved `AccessTier` and `SubagentEvent` enums to `zesdex_domain::subagent`.
- Consolidated workflow-related types into `zesdex_domain::workflow`.
- Updated references across the codebase to use the new domain models.
- Refactored tool execution logic to utilize a new `ToolExecutor` trait.
- Enhanced `AgentTurnService` to handle tool calls and events more effectively.
- Adjusted API handlers and state management to align with new domain structure.

apps/infrastructure/src/workflow/hive_mind/cycle.rs

@@ -15,7 +15,7 @@ use crate::subagent::context::SubagentContext;
 use crate::subagent::division::AccessTier;
 use crate::subagent::engine::run_agent;
 use crate::tools::ToolCtx;
-use crate::workflow::hive_mind::types::{CognitiveCycle, NodeOutput};
+use zesdex_domain::workflow::{CognitiveCycle, NodeOutput};
 
 /// Execute one cycle: run each node directive and collect outputs.
 ///
@@ -56,7 +56,7 @@ pub async fn execute_cycle(
 
     let cycle_index = cycle.index;
 
-    use crate::workflow::hive_mind::types::NodeDirective;
+    use zesdex_domain::workflow::NodeDirective;
 
     // Run all directives in this cycle concurrently.
     let handles: Vec<_> = cycle