fix: GitHub Actions push permission + submodule + dashboard Taux tab

- add permissions: contents: write + persist-credentials to workflow
- git rm --cached Market-Signal-Finder (submodule sans .gitmodules)
- consolide OIS+STIR en onglet Taux (3 sous-onglets: Courbe/Probabilités/Réunions)
- header summary: 1 ligne, fix bug Hold/Hold, taux actuel dans légende chart
- cache stale: seuil 48h → 7j pour dev local
- stale-while-revalidate: affiche cache immédiatement, refetch en arrière-plan (10s)
- redesign tooltip chart Courbe (Actuel/Sem. préc./Δsem. en bps)
- YAxis affiche taux complets (3.63% vs .63 tronqué)

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

.github/workflows/fetch-rate-data.yml

@@ -5,6 +5,9 @@ on:
     - cron: '0 * * * *'   # toutes les heures
   workflow_dispatch:        # déclenchement manuel
 
+permissions:
+  contents: write
+
 jobs:
   fetch:
     runs-on: ubuntu-latest
@@ -12,12 +15,13 @@ jobs:
       - uses: actions/checkout@v4
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
+          persist-credentials: true
 
       - uses: actions/setup-node@v4
         with:
           node-version: '20'
 
-      - name: Fetch rate probabilities from rateprobability.com
+      - name: Fetch rate probabilities (CME FedWatch / Investing.com / InvestingLive)
         run: node .github/scripts/fetch-rate-data.mjs
 
       - name: Commit updated data (if changed)