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-module-builder/assets/module-plan-template.md

@@ -0,0 +1,95 @@
+---
+title: 'Module Plan'
+status: 'ideation'
+module_name: ''
+module_code: ''
+architecture: ''
+standalone: true
+expands_module: ''
+skills_planned: []
+config_variables: []
+created: ''
+updated: ''
+---
+
+# Module Plan
+
+## Vision
+
+<!-- What this module does, who it's for, and why it matters -->
+
+## Architecture Decision
+
+<!-- Agent-centric / workflow-centric / hybrid — and the reasoning behind the choice -->
+
+## User Experience
+
+<!-- Who uses this module and what their journey looks like -->
+
+## Skills
+
+<!-- For each planned skill, copy this block: -->
+
+### {skill-name}
+
+**Type:** {agent | workflow}
+**Purpose:**
+
+**Capabilities:**
+
+| Display Name | Menu Code | Description | Action | Args | Phase | After | Before | Required | Output Location | Outputs |
+| ------------ | --------- | ----------- | ------ | ---- | ----- | ----- | ------ | -------- | --------------- | ------- |
+|              |           |             |        |      |       |       |        |          |                 |         |
+
+**Design Notes:**
+
+## Memory Architecture
+
+<!-- For multi-agent modules: personal sidecars only, personal + shared module sidecar, or shared only? -->
+<!-- What shared context should agents contribute to? (user style, content history, project assets, etc.) -->
+<!-- If shared only — consider whether a single agent is the better design -->
+
+## Configuration
+
+| Variable | Prompt | Default | Result Template | User Setting |
+| -------- | ------ | ------- | --------------- | ------------ |
+|          |        |         |                 |              |
+
+<!-- Reminder: skills should have sensible fallbacks if config hasn't been set, or ask at runtime for values they need -->
+
+## External Dependencies
+
+<!-- CLI tools, MCP servers, or other external software that skills depend on -->
+<!-- For each: what it is, which skills need it, and how the setup skill should handle it -->
+
+## UI and Visualization
+
+<!-- Does the module include dashboards, progress views, interactive interfaces, or a web app? -->
+<!-- If yes: what it shows, which skills feed into it, how it's served/installed -->
+
+## Setup Extensions
+
+<!-- Beyond config collection: web app installation, directory scaffolding, external service configuration, starter files, etc. -->
+<!-- These will need to be manually added to the setup skill after scaffolding -->
+
+## Integration
+
+<!-- Standalone: how it provides independent value -->
+<!-- Expansion: parent module, cross-module capability relationships, skills that may reference parent module ordering -->
+
+## Creative Use Cases
+
+<!-- Beyond the primary workflow — unexpected combinations, power-user scenarios, creative applications discovered during brainstorming -->
+
+## Ideas Captured
+
+<!-- Raw ideas from brainstorming — preserved for context even if not all made it into the plan -->
+
+## Build Roadmap
+
+<!-- Recommended build order for skills -->
+
+**Next steps:**
+
+1. Build each skill using **Build an Agent (BA)** or **Build a Workflow (BW)** — share this plan document as context
+2. When all skills are built, return to **Create Module (CM)** to scaffold the module infrastructure