feat(orchestrator): wire terraphim_rlm as execution backend Refs #98

- Add terraphim_rlm as optional dependency behind 'rlm' feature flag
- Add backend field to AgentDefinition for specifying execution backend
- Create rlm_dispatch module with RlmDispatcher for VM-based execution
- Add RLM budget metrics to DriftMetrics for drift evaluation
- Add observe_rlm_metrics method to NightwatchMonitor
- Add new error variants RlmError and RlmNotEnabled
- Feature-gated module and re-exports compile cleanly with/without rlm
- All tests pass with cargo test --package terraphim_orchestrator

Author: AlexMikhalev

Cargo.lock

@@ -14,6 +14,7 @@ terraphim_router = { path = "../terraphim_router", version = "1.0.0" }
 terraphim_types = { path = "../terraphim_types", version = "1.0.0" }
 terraphim_tracker = { path = "../terraphim_tracker", version = "1.0.0" }
 terraphim_symphony = { path = "../terraphim_symphony", version = "1.0.0" }
+terraphim_rlm = { path = "../terraphim_rlm", version = "1.0.0", optional = true }
 
 # Core dependencies
 tokio = { version = "1.0", features = ["full", "signal"] }
@@ -35,6 +36,10 @@ toml = "0.9"
 # Template rendering
 handlebars = "6.3"
 
+[features]
+default = []
+rlm = ["dep:terraphim_rlm"]
+
 [dev-dependencies]
 tokio-test = "0.4"
 tempfile = "3.27"