wip(tickets): backend createdBy (#5) + bulk status/priority/delete (#6)

Ajoute created_by sur IssueIndexEntry/TicketSummaryDto + filtre createdBy
(#5), et les use cases BulkUpdateIssueStatus/Priority + BulkDeleteIssues
avec les DTO/outils MCP idea_ticket_bulk_* associés (#6).

NON VERT : BulkDeleteIssues::execute référence BatchIssueResult::deleted(),
constructeur pas encore ajouté à BatchIssueResult (seuls ok/err existent) ->
`cargo check` échoue (E0599 dans application::issues::mod). Reste à
DevBackend avant toute QA/merge.

Branché sur feature/sdk-integration (dépend du commit #2 dans
orchestrator/mcp/server.rs et tools.rs) ; à rebaser sur develop une fois
feature/sdk-integration mergé.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

crates/infrastructure/tests/issue_store.rs

@@ -2,7 +2,7 @@ use std::path::PathBuf;
 use std::str::FromStr;
 
 use domain::{
-    AgentIssueRef, AgentIssueRole, Issue, IssueActor, IssueId, IssueListFilter,
+    AgentId, AgentIssueRef, AgentIssueRole, Issue, IssueActor, IssueId, IssueListFilter,
     IssueNumberAllocator, IssuePriority, IssueRef, IssueStatus, IssueStore, IssueStoreError,
     MarkdownDoc, ProjectPath, SprintId,
 };
@@ -184,6 +184,60 @@ async fn issue_store_lists_by_index_filters_with_empty_or_and_and_semantics() {
     assert_eq!(by_status_and_priority[0].title, "Beta");
 }
 
+#[tokio::test]
+async fn issue_store_filters_by_created_by_from_index() {
+    let tmp = TempDir::new();
+    let root = tmp.root();
+    let store = FsIssueStore::new();
+    let agent_id = AgentId::new_random();
+    store
+        .create(&root, &issue(&root, 1, "User ticket"))
+        .await
+        .unwrap();
+    let agent_ticket = Issue::new(
+        IssueId::new_random(),
+        domain::IssueNumber::new(2).unwrap(),
+        "Agent ticket",
+        MarkdownDoc::new("Initial description"),
+        IssueStatus::Open,
+        IssuePriority::High,
+        MarkdownDoc::new("Initial carnet"),
+        Vec::new(),
+        Vec::new(),
+        IssueActor::Agent { agent_id },
+        1_000,
+    )
+    .unwrap();
+    store.create(&root, &agent_ticket).await.unwrap();
+
+    let by_user = store
+        .list(
+            &root,
+            IssueListFilter {
+                created_by: Some(IssueActor::User),
+                ..IssueListFilter::default()
+            },
+        )
+        .await
+        .unwrap();
+    let by_agent = store
+        .list(
+            &root,
+            IssueListFilter {
+                created_by: Some(IssueActor::Agent { agent_id }),
+                ..IssueListFilter::default()
+            },
+        )
+        .await
+        .unwrap();
+
+    assert_eq!(by_user.len(), 1);
+    assert_eq!(by_user[0].title, "User ticket");
+    assert_eq!(by_agent.len(), 1);
+    assert_eq!(by_agent[0].title, "Agent ticket");
+    assert_eq!(by_agent[0].created_by, IssueActor::Agent { agent_id });
+}
+
 #[tokio::test]
 async fn issue_store_text_filter_matches_exact_ref_or_number_without_numeric_substring() {
     let tmp = TempDir::new();