feat: implémentation complète du système Célestopol 1922 pour FoundryVTT v13

- DataModels (character, npc, anomaly, aspect, attribute, equipment)
- ApplicationV2 sheets (character 5 tabs, npc 3 tabs, 4 item sheets)
- DialogV2 pour les jets de dés avec phase de lune
- Templates Handlebars complets (fiches PJ/PNJ, items, jet, chat)
- Styles LESS → CSS compilé (thème vert foncé / orange CopaseticNF)
- i18n fr.json complet (clés CELESTOPOL.*)
- Point d'entrée fvtt-celestopol.mjs avec hooks init/ready
- Assets : polices CopaseticNF, images UI, icônes items
- Mise à jour copilot-instructions.md avec l'architecture réelle

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/copilot-instructions.md

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+# Copilot Instructions — fvtt-celestopol
+
+## Project Overview
+
+This is a **Foundry VTT system** for **Célestopol 1922**, a French tabletop RPG set in an art-deco 1922 universe. The project targets FoundryVTT v13+ and is developed in French.
+
+The reference rulebooks are in `__regles/` (gitignored):
+- *Célestopol 1922 Livre de base* — core rulebook
+- *Célestopol 1922 Fiches de prêts à jouer* — pre-generated character sheets
+
+## Architecture
+
+This system uses **FoundryVTT v13 DataModels + ApplicationV2** — NOT the legacy template.json / AppV1 approach.
+
+```
+fvtt-celestopol.mjs          # Main entry point (Hooks.once("init"))
+module/
+  config/system.mjs          # All game constants (SYSTEM export)
+  models/                    # TypeDataModel subclasses (character, npc, items)
+  documents/                 # Actor, Item, ChatMessage, Roll wrappers
+  applications/sheets/       # AppV2 sheets (HandlebarsApplicationMixin)
+lang/fr.json                 # French i18n (key prefix: CELESTOPOL.*)
+styles/                      # LESS source files
+css/                         # Compiled CSS (via gulp)
+templates/                   # Handlebars (.hbs) templates
+assets/fonts/                # CopaseticNF art-deco font
+assets/ui/                   # Background images
+assets/icons/                # Item icons
+packs-system/                # Source files for compendium packs
+```
+
+## DataModels (no template.json)
+
+- Extend `foundry.abstract.TypeDataModel`
+- Schema in `static defineSchema()` using `foundry.data.fields.*`
+- `prepareDerivedData()` for computed values
+- Files: `module/models/character.mjs`, `npc.mjs`, `items.mjs`
+
+## ApplicationV2 / Sheets
+
+- Actor sheets: `HandlebarsApplicationMixin(foundry.applications.sheets.ActorSheetV2)`
+- Item sheets: `HandlebarsApplicationMixin(foundry.applications.sheets.ItemSheetV2)`
+- `static DEFAULT_OPTIONS` for config; `static PARTS` for templates
+- `_prepareContext()` for base context; `_preparePartContext(partId, context)` for per-tab
+- Edit/Play mode toggle via `_sheetMode` + `isPlayMode`/`isEditMode` getters
+- Actions: `static #onXxx(event, target)` private static methods in `DEFAULT_OPTIONS.actions`
+- `form: { submitOnChange: true }` enables live saving
+
+## Roll Mechanics
+
+- Pool of d6 dice: `nbDice = max(1, skillValue + woundMalus)`
+- Formula: `{n}d6 [+ moonBonus + modifier]`
+- Moon phase bonus: Nouvelle Lune=0, Croissants=+1, Gibbeuse=+2, Pleine Lune=+3
+- Compare total vs difficulty threshold (normal=7)
+- Wound malus: levels 1-2=0, 3-4=-1, 5-6=-2, 7=-3, 8=-999 (out)
+- DialogV2 for roll configuration: `foundry.applications.api.DialogV2.wait(...)`
+
+## Game Data (4 stats × 4 skills)
+
+- **Âme**: Artifice, Attraction, Coercition, Faveur
+- **Corps**: Échauffourée, Effacement, Mobilité, Prouesse
+- **Cœur**: Appréciation, Arts, Inspiration, Traque
+- **Esprit**: Instruction, Merveilleux technologique, Raisonnement, Traitement
+
+**Tracks**: Blessures (8 niveaux), Destin (8), Spleen (8)  
+**Anomalies**: 9 types (none + 8)  
+**Factions**: 8 standard + 2 custom
+
+## Build
+
+```bash
+npm install          # Install dev deps
+npx gulp css         # Compile LESS → css/fvtt-celestopol.css (once)
+npx gulp             # Compile + watch
+```
+
+## Visual Style
+
+- Font: **CopaseticNF** (Regular + Bold, in `assets/fonts/`) — art-deco style
+- Header bg color: `rgb(12, 76, 12)` (dark green) with orange text (`#e07b00`)
+- Sheet header texture: `assets/ui/fond_cadrille.jpg`
+- CSS variables: `--cel-green`, `--cel-orange`, `--cel-font-title`, etc.
+
+## Language
+
+All in-game text, labels, and code comments should be in **French**. Code identifiers may be English. All i18n keys use the `CELESTOPOL.*` prefix (see `lang/fr.json`).
+