test(jira): add JiraLink model and jira_service tests [FASE-1.1]

Model and migration b020 were already present; adds regression coverage for persistence, schema validation, and link CRUD with Jira disabled.

backend/tests/test_jira_link.py

@@ -0,0 +1,93 @@
+"""Tests for Jira link model and jira_service link helpers (FASE-1.1).
+
+Verifies persistence with SQLite test DB and link creation when Jira is disabled.
+API routes are covered indirectly via jira_service (same code path as the router).
+"""
+
+import uuid
+
+import pytest
+from pydantic import ValidationError
+
+from app.models.jira_link import JiraLink, JiraLinkEntityType, JiraSyncDirection
+from app.schemas.jira_schema import JiraLinkCreate
+from app.services import jira_service
+
+
+def test_jira_link_persist_and_query(db, admin_user):
+    entity_id = uuid.uuid4()
+    link = JiraLink(
+        entity_type=JiraLinkEntityType.test,
+        entity_id=entity_id,
+        jira_issue_key="PROJ-42",
+        jira_issue_id="10001",
+        sync_direction=JiraSyncDirection.bidirectional,
+        created_by=admin_user.id,
+        sync_metadata={"foo": "bar"},
+    )
+    db.add(link)
+    db.commit()
+    db.refresh(link)
+
+    loaded = db.query(JiraLink).filter(JiraLink.id == link.id).one()
+    assert loaded.entity_type == JiraLinkEntityType.test
+    assert loaded.entity_id == entity_id
+    assert loaded.jira_issue_key == "PROJ-42"
+    assert loaded.sync_metadata == {"foo": "bar"}
+    assert loaded.created_by == admin_user.id
+
+
+def test_jira_link_create_schema_accepts_valid_issue_key():
+    body = JiraLinkCreate(
+        entity_type=JiraLinkEntityType.campaign,
+        entity_id=uuid.uuid4(),
+        jira_issue_key="ABC-1",
+    )
+    assert body.jira_issue_key == "ABC-1"
+    assert body.sync_direction == JiraSyncDirection.bidirectional
+
+
+def test_jira_link_create_schema_rejects_invalid_issue_key():
+    with pytest.raises(ValidationError):
+        JiraLinkCreate(
+            entity_type=JiraLinkEntityType.test,
+            entity_id=uuid.uuid4(),
+            jira_issue_key="proj-123",
+        )
+
+
+def test_create_link_via_service_persists(db, admin_user):
+    eid = uuid.uuid4()
+    link = jira_service.create_link(
+        db,
+        entity_type=JiraLinkEntityType.test,
+        entity_id=eid,
+        jira_issue_key="TST-99",
+        sync_direction=JiraSyncDirection.bidirectional,
+        created_by=admin_user.id,
+    )
+    db.commit()
+    db.refresh(link)
+    assert link.jira_issue_key == "TST-99"
+    assert link.entity_id == eid
+
+
+def test_list_links_filters_by_entity(db, admin_user):
+    eid = uuid.uuid4()
+    jira_service.create_link(
+        db,
+        entity_type=JiraLinkEntityType.technique,
+        entity_id=eid,
+        jira_issue_key="TECH-7",
+        sync_direction=JiraSyncDirection.jira_to_aegis,
+        created_by=admin_user.id,
+    )
+    db.commit()
+    rows = jira_service.list_links(
+        db,
+        entity_type=JiraLinkEntityType.technique,
+        entity_id=eid,
+    )
+    assert len(rows) == 1
+    assert rows[0].jira_issue_key == "TECH-7"
+    assert rows[0].sync_direction == JiraSyncDirection.jira_to_aegis