fix(campaigns/templates): clarify who refunds whom for early cancellation

User feedback: the prorata disclaimer was semantically wrong — both FR
("le prorata du montant est remboursable") and EN ("we'll refund the
pro-rated amount") read as if TARGO would refund the customer, when
actually the customer needs to refund the unused portion of the gift
they received if they cancel within the commitment period.

Plus: add the explicit per-month rate ($20/month at $60 / 3 months) so
the customer knows exactly what they'd owe at any cancellation date.

FR:
  before — "🪂 En cas de départ avant {{commitment_months}} mois,
            le prorata du montant est remboursable."
  after  — "🪂 Si tu résilies avant {{commitment_months}} mois,
            tu rembourses le prorata non utilisé (20 $/mois)."

EN:
  before — "🪂 If you decide to leave before {{commitment_months}}
            months, we'll refund the pro-rated amount."
  after  — "🪂 If you cancel before {{commitment_months}} months,
            you refund the unused pro-rated amount ($20/month)."

Both changes:
  • Subject clarified: customer refunds, not TARGO
  • Added explicit per-month value for transparency
  • Kept warm tone (informal "tu" / "you")
  • Mustache {{commitment_months}} preserved

Applied directly to .html + .json via string substitution (preserves
the Unlayer design tree intact except for that one phrase). The
"$20/month" figure is hardcoded for the current $60/3-month campaign;
a future {{monthly_prorata}} computed variable would generalize but
isn't needed yet.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/campaigns/templates/gift-email-en.html

@@ -519,7 +519,7 @@ table, td { color: #1B2E24; } #u_body a { color: #00C853; text-decoration: under
                   
       <div
          style="font-family:Plus Jakarta Sans, Helvetica, Arial, sans-serif;font-size:14px;line-height:1.5;text-align:left;color:#6b7280;"
-      >🪂 If you decide to leave before {{commitment_months}} months, we'll refund the pro-rated amount.</div>
+      >🪂 If you cancel before {{commitment_months}} months, you refund the unused pro-rated amount ($20/month).</div>
     
                 </td>
               </tr>

scripts/campaigns/templates/gift-email-fr.html

@@ -519,7 +519,7 @@ table, td { color: #1B2E24; } #u_body a { color: #00C853; text-decoration: under
                   
       <div
          style="font-family:Plus Jakarta Sans, Helvetica, Arial, sans-serif;font-size:14px;line-height:1.5;text-align:left;color:#6b7280;"
-      >🪂 En cas de départ avant {{commitment_months}} mois, le prorata du montant est remboursable.</div>
+      >🪂 Si tu résilies avant {{commitment_months}} mois, tu rembourses le prorata non utilisé (20 $/mois).</div>
     
                 </td>
               </tr>

services/targo-hub/templates/gift-email-en.html

@@ -519,7 +519,7 @@ table, td { color: #1B2E24; } #u_body a { color: #00C853; text-decoration: under
                   
       <div
          style="font-family:Plus Jakarta Sans, Helvetica, Arial, sans-serif;font-size:14px;line-height:1.5;text-align:left;color:#6b7280;"
-      >🪂 If you decide to leave before {{commitment_months}} months, we'll refund the pro-rated amount.</div>
+      >🪂 If you cancel before {{commitment_months}} months, you refund the unused pro-rated amount ($20/month).</div>
     
                 </td>
               </tr>

services/targo-hub/templates/gift-email-fr.html

@@ -519,7 +519,7 @@ table, td { color: #1B2E24; } #u_body a { color: #00C853; text-decoration: under
                   
       <div
          style="font-family:Plus Jakarta Sans, Helvetica, Arial, sans-serif;font-size:14px;line-height:1.5;text-align:left;color:#6b7280;"
-      >🪂 En cas de départ avant {{commitment_months}} mois, le prorata du montant est remboursable.</div>
+      >🪂 Si tu résilies avant {{commitment_months}} mois, tu rembourses le prorata non utilisé (20 $/mois).</div>
     
                 </td>
               </tr>