feat: Calculer automatiquement les moyennes après chaque saisie de notes

Les enseignants ont besoin de moyennes à jour immédiatement après la
publication ou modification des notes, sans attendre un batch nocturne.

Le système recalcule via Domain Events synchrones : statistiques
d'évaluation (min/max/moyenne/médiane), moyennes matières pondérées
(normalisation /20), et moyenne générale par élève. Les résultats sont
stockés dans des tables dénormalisées avec cache Redis (TTL 5 min).

Trois endpoints API exposent les données avec contrôle d'accès par rôle.
Une commande console permet le backfill des données historiques au
déploiement.

.agents/skills/bmad-create-architecture/workflow.md

@@ -0,0 +1,38 @@
+# Architecture Workflow
+
+**Goal:** Create comprehensive architecture decisions through collaborative step-by-step discovery that ensures AI agents implement consistently.
+
+**Your Role:** You are an architectural facilitator collaborating with a peer. This is a partnership, not a client-vendor relationship. You bring structured thinking and architectural knowledge, while the user brings domain expertise and product vision. Work together as equals to make decisions that prevent implementation conflicts.
+
+---
+
+## WORKFLOW ARCHITECTURE
+
+This uses **micro-file architecture** for disciplined execution:
+
+- Each step is a self-contained file with embedded rules
+- Sequential progression with user control at each step
+- Document state tracked in frontmatter
+- Append-only document building through conversation
+- You NEVER proceed to a step file if the current step file indicates the user must approve and indicate continuation.
+
+---
+
+## INITIALIZATION
+
+### Configuration Loading
+
+Load config from `{project-root}/_bmad/bmm/config.yaml` and resolve:
+
+- `project_name`, `output_folder`, `planning_artifacts`, `user_name`
+- `communication_language`, `document_output_language`, `user_skill_level`
+- `date` as system-generated current datetime
+- ✅ YOU MUST ALWAYS SPEAK OUTPUT In your Agent communication style with the config `{communication_language}`
+
+---
+
+## EXECUTION
+
+Read fully and follow: `./steps/step-01-init.md` to begin the workflow.
+
+**Note:** Input document discovery and all initialization protocols are handled in step-01-init.md.