feat(tickets): tri de la liste de tickets côté backend (#21)

Ajoute le paramètre de tri dans TicketListQuery et l'expose via
ticket_list (surface app-tauri + MCP). Ports et adaptateur mock
frontend alignés sur le contrat de tri. La partie UI (contrôle de tri
dans TicketFacetsBar) suivra dans un commit frontend dédié.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/infrastructure/src/orchestrator/mcp/tickets.rs

@@ -74,6 +74,15 @@ pub fn catalogue() -> Vec<ToolDef> {
     let ticket_ref = json!({ "type": "string", "pattern": "^#[1-9][0-9]*$" });
     let status = json!({ "type": "string", "enum": ["open", "inProgress", "QA", "closed"] });
     let priority = json!({ "type": "string", "enum": ["low", "medium", "high", "critical"] });
+    let sort = json!({
+        "type": "object",
+        "properties": {
+            "field": { "type": "string", "enum": ["number", "priority", "status", "title"] },
+            "direction": { "type": "string", "enum": ["asc", "desc"] }
+        },
+        "required": ["field", "direction"],
+        "additionalProperties": false
+    });
     let link_kind = json!({
         "type": "string",
         "enum": ["relatesTo", "blocks", "blockedBy", "duplicates", "dependsOn"]
@@ -137,6 +146,7 @@ pub fn catalogue() -> Vec<ToolDef> {
                     },
                     "assignedAgentId": { "type": "string", "format": "uuid" },
                     "text": { "type": "string" },
+                    "sort": sort.clone(),
                     "limit": { "type": "integer", "minimum": 1 },
                     "cursor": { "type": "string" }
                 },