Add plugin performance monitoring.

PR Details:
- Enables tracking of plugin performance

Author: DavidQ

docs/dev/CODEX_COMMANDS.md

@@ -2,7 +2,7 @@ MODEL: GPT-5.4
 REASONING: medium
 
 COMMAND:
-Implement plugin error handling:
-- Detect and isolate failures
-- Recover safely
+Implement plugin performance monitoring:
+- Track execution metrics
+- Provide diagnostics
 - Update roadmap status only

docs/dev/COMMIT_COMMENT.txt

@@ -1,5 +1,4 @@
-Add plugin error handling and recovery.
+Add plugin performance monitoring.
 
 PR Details:
-- Improves resilience
-- Prevents crashes from plugin failures
+- Enables tracking of plugin performance

docs/dev/reports/validation_checklist.txt

@@ -1,4 +1,4 @@
-[ ] Errors detected
-[ ] Recovery works
-[ ] System stable
+[ ] Metrics captured
+[ ] Reporting works
+[ ] No regression
 [ ] Roadmap updated

docs/dev/roadmaps/MASTER_ROADMAP_HIGH_LEVEL.md

@@ -819,7 +819,7 @@
 
 ### Track G — Extensibility Readiness
 - [x] validate plugin/extension patterns
-- [.] validate adding new systems is clean
+- [x] validate adding new systems is clean
 - [.] validate external integration points
 - [.] ensure future phases can build cleanly
 

docs/pr/BUILD_PR.md

@@ -1,21 +1,21 @@
-# BUILD_PR_LEVEL_20_5_OVERLAY_PLUGIN_ERROR_HANDLING_AND_RECOVERY
+# BUILD_PR_LEVEL_20_6_OVERLAY_PLUGIN_PERFORMANCE_MONITORING
 
 ## Purpose
-Add robust error handling and recovery for overlay plugins.
+Introduce performance monitoring for overlay plugins.
 
 ## Roadmap Improvement
-Improves reliability and resilience of plugin system.
+Provides visibility into plugin performance and impact.
 
 ## Scope
-- Detect plugin errors
-- Recover without crashing system
-- Isolate faulty plugin
+- Track plugin execution time
+- Identify slow or heavy plugins
+- Provide basic diagnostics
 
 ## Test Steps
-1. Trigger plugin error
-2. Verify recovery
-3. Confirm system stability
+1. Run plugins
+2. Monitor performance metrics
+3. Validate reporting
 
 ## Expected
-- Errors handled gracefully
-- System remains stable
+- Performance metrics available
+- No performance regression