feat: Phase 4 — module Notes complet

Backend :
- schemas/notes.py : NoteCreate/Update/Response + AttachmentResponse
- api/notes.py : CRUD + FTS français (plainto_tsquery) + filtres rapides
  (has_photo/audio/gps/tag/category) + pièces jointes (image/audio)
- main.py : enregistrement /api/notes

Frontend :
- api/notes.ts : fetchNotes/create/update/delete + add/deleteAttachment
- NoteForm.tsx : titre, contenu, catégorie, tags CSV, GPS
- NotesPage.tsx : liste mobile (chronologique) + grille laptop, FAB +,
  enregistrement audio inline (MediaRecorder), upload photo, filtres rapides

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/schemas/notes.py

@@ -0,0 +1,45 @@
+import uuid
+from datetime import datetime
+from decimal import Decimal
+from pydantic import BaseModel, ConfigDict
+
+
+class AttachmentResponse(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+    id: uuid.UUID
+    file_path: str | None
+    thumbnail_path: str | None
+    file_type: str | None
+    original_name: str | None
+    created_at: datetime
+
+
+class NoteCreate(BaseModel):
+    title: str | None = None
+    content: str
+    category: str | None = None
+    tags: list[str] = []
+    gps_lat: Decimal | None = None
+    gps_lon: Decimal | None = None
+
+
+class NoteUpdate(BaseModel):
+    title: str | None = None
+    content: str | None = None
+    category: str | None = None
+    tags: list[str] | None = None
+    gps_lat: Decimal | None = None
+    gps_lon: Decimal | None = None
+
+
+class NoteResponse(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+    id: uuid.UUID
+    title: str | None
+    content: str
+    category: str | None
+    tags: list[str]
+    gps_lat: Decimal | None
+    gps_lon: Decimal | None
+    created_at: datetime
+    attachments: list[AttachmentResponse]