Toolbox 30rem sticky + accordéons collapsibles + renommage libreDecision

- Boîte à outils élargie à 30rem (×1.75) — flottante sticky, zéro scroll visible
- ToolboxSection : nouveau composant accordéon générique (chevron, défaut fermé)
- ToolboxVignette : titre cliquable, bullets/actions cachés par défaut
- 4 pages : ContextMapper/SocioElection/WorkflowMilestones/inertie → ToolboxSection
- Suppression doublon SectionLayout (common/) — conflit de nommage résolu
- Renommage complet Glibredecision → libreDecision dans configs/docker/CI
- README.md + CONTRIBUTING.md ajoutés

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

backend/app/services/sanctuary_service.py

@@ -1,6 +1,6 @@
 """Sanctuary service: immutable archival to IPFS + on-chain hash.
 
-The sanctuary is the immutable layer of Glibredecision.  Every adopted
+The sanctuary is the immutable layer of libreDecision.  Every adopted
 document version, decision result, or vote tally is hashed (SHA-256),
 stored on IPFS, and anchored on-chain via system.remark.
 """
@@ -241,7 +241,7 @@ async def _anchor_on_chain(content_hash: str) -> tuple[str | None, int | None]:
         call = substrate.compose_call(
             call_module="System",
             call_function="remark",
-            call_params={"remark": f"glibredecision:sanctuary:{content_hash}"},
+            call_params={"remark": f"libredecision:sanctuary:{content_hash}"},
         )
         extrinsic = substrate.create_signed_extrinsic(call=call, keypair=keypair)
         receipt = substrate.submit_extrinsic(extrinsic, wait_for_inclusion=True)