[CA-13] Update generate_charges.py to save charges in Supabase

[luigischmitt]

Goal

Modify the charge generation job to save each created charge in Supabase, enabling complete txid tracking per member.

Context

Currently generate_charges.py creates the charge in Efí and sends an email, but doesn't store the txid anywhere. This makes it difficult to:

• Know which txid belongs to which member
• Reconcile payments correctly
• Audit old charges

Required Changes

src/jobs/generate_charges.py

# After creating charge in Efí
charge = efi_service.create_pix_charge(...)

# Save to Supabase
supabase_service.create_charge(
    member_name=member.name,
    txid=charge.txid,
    amount=CHARGE_AMOUNT,
    month=month_column,
    year=date.today().year,
)

Tasks

• Import SupabaseService in generate_charges.py
• Add call to save charge after creation
• Ensure Supabase errors don't block the main flow (try/except with logging)

Dependencies

• Depends on [CA-12] Integrate Supabase as internal database #21 (CA-12 - Supabase integration)