Document validation architecture and renderer faithfulness findings

- document Entity Registry and Meeting Context V2 architecture
- preserve meeting_context.yaml as the authoritative meeting-specific input
- define immutable authoritative metadata across all pipeline stages
- restrict Constraint Repair to deterministic structured-data operations
- record BUG-003 root cause and deferred entity-verification resolution
- document BUG-005 attendance-consistency design
- add BUG-006 renderer faithfulness root-cause analysis
- distinguish Engineering Readiness from Practical Usability
- update the persistent regression bug tracker

docs/meeting-context.md

@@ -26,6 +26,48 @@ Supported metadata:
 - abbreviations
 - relevant products, projects, systems, locations and technical terms
 
+## Future Direction: V2
+
+Accepted Architecture. Implementation deferred.
+
+Meeting Context V2 should be generated from an interactive entity confirmation
+workflow after Whisper transcription:
+
+```text
+Whisper
+    ↓
+Entity Detection
+    ↓
+User Confirmation
+    ↓
+Entity Registry Update
+    ↓
+Meeting Context Builder
+    ↓
+meeting_context.yaml
+    ↓
+Extraction Pipeline
+```
+
+The YAML remains the extraction interface and the authoritative
+meeting-specific Point of Truth for a meeting run. It should become a
+meeting-specific snapshot generated or assisted from the Entity Registry, user
+confirmations and meeting metadata.
+
+The Entity Registry is the persistent cross-meeting knowledge source for
+confirmed entities, aliases and organizational metadata. It stores stable
+internal identifiers and never learns automatically. The Registry must not
+override explicit meeting-specific confirmations, and Registry changes after a
+meeting run must not silently change the historical Meeting Context used for
+that run.
+
+Unknown names should be explicitly classified by the user as meeting
+participant, mentioned person, external person, transcription error or ignore.
+Similarity suggestions for spelling variants, Whisper variants, umlaut
+handling and OCR-like mistakes require explicit confirmation.
+
+See `docs/adr-meeting-context-v2-entity-registry.md`.
+
 ## File Locations
 
 - Generic template: `samples/templates/meeting_context.template.yaml`