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-workflow-builder/references/script-standards.md

@@ -0,0 +1,92 @@
+# Script Creation Standards
+
+When building scripts for a skill, follow these standards to ensure portability and zero-friction execution. Skills must work across macOS, Linux, and Windows (native, Git Bash, and WSL).
+
+## Python Over Bash
+
+**Always favor Python for script logic.** Bash is not portable — it fails or behaves inconsistently on Windows (Git Bash is MSYS2-based, not a full Linux shell; WSL bash can conflict with Git Bash on PATH; PowerShell is a different language entirely). Python with `uv run` works identically on all platforms.
+
+**Safe bash commands** — these work reliably across all environments and are fine to use directly:
+
+- `git`, `gh` — version control and GitHub CLI
+- `uv run` — Python script execution with automatic dependency handling
+- `npm`, `npx`, `pnpm` — Node.js ecosystem
+- `mkdir -p` — directory creation
+
+**Everything else should be Python** — piping, `jq`, `grep`, `sed`, `awk`, `find`, `diff`, `wc`, and any non-trivial logic. Even `sed -i` behaves differently on macOS vs Linux. If it's more than a single safe command, write a Python script.
+
+## Favor the Standard Library
+
+Always prefer Python's standard library over external dependencies. The stdlib is pre-installed everywhere, requires no `uv run`, and has zero supply-chain risk. Common stdlib modules that cover most script needs:
+
+- `json` — JSON parsing and output
+- `pathlib` — cross-platform path handling
+- `re` — pattern matching
+- `argparse` — CLI interface
+- `collections` — counters, defaultdicts
+- `difflib` — text comparison
+- `ast` — Python source analysis
+- `csv`, `xml.etree` — data formats
+
+Only pull in external dependencies when the stdlib genuinely cannot do the job (e.g., `tiktoken` for accurate token counting, `pyyaml` for YAML parsing, `jsonschema` for schema validation). **External dependencies must be confirmed with the user during the build process** — they add install-time cost, supply-chain surface, and require `uv` to be available.
+
+## PEP 723 Inline Metadata (Required)
+
+Every Python script MUST include a PEP 723 metadata block. For scripts with external dependencies, use the `uv run` shebang:
+
+```python
+#!/usr/bin/env -S uv run --script
+# /// script
+# requires-python = ">=3.10"
+# dependencies = ["pyyaml>=6.0", "jsonschema>=4.0"]
+# ///
+```
+
+For scripts using only the standard library, use a plain Python shebang but still include the metadata block:
+
+```python
+#!/usr/bin/env python3
+# /// script
+# requires-python = ">=3.10"
+# ///
+```
+
+**Key rules:**
+
+- The shebang MUST be line 1 — before the metadata block
+- Always include `requires-python`
+- List all external dependencies with version constraints
+- Never use `requirements.txt`, `pip install`, or expect global package installs
+- The shebang is a Unix convenience — cross-platform invocation relies on `uv run scripts/foo.py`, not `./scripts/foo.py`
+
+## Invocation in SKILL.md
+
+How a built skill's SKILL.md should reference its scripts:
+
+- **Scripts with external dependencies:** `uv run scripts/analyze.py {args}`
+- **Stdlib-only scripts:** `python3 scripts/scan.py {args}` (also fine to use `uv run` for consistency)
+
+`uv run` reads the PEP 723 metadata, silently caches dependencies in an isolated environment, and runs the script — no user prompt, no global install. Like `npx` for Python.
+
+## Graceful Degradation
+
+Skills may run in environments where Python or `uv` is unavailable (e.g., claude.ai web). Scripts should be the fast, reliable path — but the skill must still deliver its outcome when execution is not possible.
+
+**Pattern:** When a script cannot execute, the LLM performs the equivalent work directly. The script's `--help` documents what it checks, making this fallback natural. Design scripts so their logic is understandable from their help output and the skill's context.
+
+In SKILL.md, frame script steps as outcomes, not just commands:
+
+- Good: "Validate path conventions (run `scripts/scan-paths.py --help` for details)"
+- Avoid: "Execute `python3 scripts/scan-paths.py`" with no context about what it does
+
+## Script Interface Standards
+
+- Implement `--help` via `argparse` (single source of truth for the script's API)
+- Accept target path as a positional argument
+- `-o` flag for output file (default to stdout)
+- Diagnostics and progress to stderr
+- Exit codes: 0=pass, 1=fail, 2=error
+- `--verbose` flag for debugging
+- Output valid JSON to stdout
+- No interactive prompts, no network dependencies
+- Tests in `scripts/tests/`