Add follow-up task generation on approve

When approving a task, PM agent analyzes pipeline output and creates
follow-up tasks automatically (e.g. security audit → 8 fix tasks).

core/followup.py:
  generate_followups() — collects pipeline output, runs followup agent,
  parses JSON task list, creates tasks with parent_task_id linkage.
  Handles: bare arrays, {tasks:[...]} wrappers, invalid JSON, empty.

agents/prompts/followup.md — PM prompt for analyzing results and
  creating actionable follow-up tasks with priority from severity.

CLI: kin approve <task_id> [--followup] [--decision "text"]
API: POST /api/tasks/{id}/approve {create_followups: true}
  Returns {status, decision, followup_tasks: [...]}

Frontend (TaskDetail approve modal):
  - Checkbox "Create follow-up tasks" (default ON)
  - Loading state during generation
  - Results view: list of created tasks with links to /task/:id

ProjectView: tasks show "from VDOL-001" for follow-ups.

13 new tests (followup), 125 total, all passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_followup.py

@@ -0,0 +1,141 @@
+"""Tests for core/followup.py — follow-up task generation."""
+
+import json
+import pytest
+from unittest.mock import patch, MagicMock
+
+from core.db import init_db
+from core import models
+from core.followup import generate_followups, _collect_pipeline_output, _next_task_id
+
+
+@pytest.fixture
+def conn():
+    c = init_db(":memory:")
+    models.create_project(c, "vdol", "ВДОЛЬ", "~/projects/vdolipoperek",
+                          tech_stack=["vue3"], language="ru")
+    models.create_task(c, "VDOL-001", "vdol", "Security audit",
+                       status="done", brief={"route_type": "security_audit"})
+    # Add some pipeline logs
+    models.log_agent_run(c, "vdol", "security", "execute",
+                         task_id="VDOL-001",
+                         output_summary=json.dumps({
+                             "summary": "8 уязвимостей найдено",
+                             "findings": [
+                                 {"severity": "HIGH", "title": "Admin endpoint без auth",
+                                  "file": "index.js", "line": 42},
+                                 {"severity": "HIGH", "title": "SEO endpoints без auth",
+                                  "file": "index.js", "line": 88},
+                                 {"severity": "MEDIUM", "title": "Нет rate limiting на login",
+                                  "file": "auth.js", "line": 15},
+                             ],
+                         }, ensure_ascii=False),
+                         success=True)
+    yield c
+    c.close()
+
+
+class TestCollectPipelineOutput:
+    def test_collects_all_steps(self, conn):
+        output = _collect_pipeline_output(conn, "VDOL-001")
+        assert "security" in output
+        assert "Admin endpoint" in output
+
+    def test_empty_for_no_logs(self, conn):
+        assert _collect_pipeline_output(conn, "NONEXISTENT") == ""
+
+
+class TestNextTaskId:
+    def test_increments(self, conn):
+        assert _next_task_id(conn, "vdol") == "VDOL-002"
+
+    def test_handles_obs_ids(self, conn):
+        # OBS tasks shouldn't interfere with numbering
+        models.create_task(conn, "VDOL-OBS-001", "vdol", "Obsidian task")
+        assert _next_task_id(conn, "vdol") == "VDOL-002"
+
+
+class TestGenerateFollowups:
+    @patch("agents.runner._run_claude")
+    def test_creates_followup_tasks(self, mock_claude, conn):
+        mock_claude.return_value = {
+            "output": json.dumps([
+                {"title": "Fix admin auth", "type": "hotfix", "priority": 2,
+                 "brief": "Add requireAuth to admin endpoints"},
+                {"title": "Add rate limiting", "type": "feature", "priority": 4,
+                 "brief": "Rate limit login to 5/15min"},
+            ]),
+            "returncode": 0,
+        }
+
+        created = generate_followups(conn, "VDOL-001")
+
+        assert len(created) == 2
+        assert created[0]["id"] == "VDOL-002"
+        assert created[1]["id"] == "VDOL-003"
+        assert created[0]["title"] == "Fix admin auth"
+        assert created[0]["parent_task_id"] == "VDOL-001"
+        assert created[0]["priority"] == 2
+        assert created[1]["parent_task_id"] == "VDOL-001"
+
+        # Brief should contain source reference
+        assert created[0]["brief"]["source"] == "followup:VDOL-001"
+        assert created[0]["brief"]["route_type"] == "hotfix"
+
+    @patch("agents.runner._run_claude")
+    def test_handles_empty_response(self, mock_claude, conn):
+        mock_claude.return_value = {"output": "[]", "returncode": 0}
+        assert generate_followups(conn, "VDOL-001") == []
+
+    @patch("agents.runner._run_claude")
+    def test_handles_wrapped_response(self, mock_claude, conn):
+        """PM might return {tasks: [...]} instead of bare array."""
+        mock_claude.return_value = {
+            "output": json.dumps({"tasks": [
+                {"title": "Fix X", "priority": 3},
+            ]}),
+            "returncode": 0,
+        }
+        created = generate_followups(conn, "VDOL-001")
+        assert len(created) == 1
+
+    @patch("agents.runner._run_claude")
+    def test_handles_invalid_json(self, mock_claude, conn):
+        mock_claude.return_value = {"output": "not json", "returncode": 0}
+        assert generate_followups(conn, "VDOL-001") == []
+
+    def test_no_logs_returns_empty(self, conn):
+        models.create_task(conn, "VDOL-999", "vdol", "Empty task")
+        assert generate_followups(conn, "VDOL-999") == []
+
+    def test_nonexistent_task(self, conn):
+        assert generate_followups(conn, "NOPE") == []
+
+    def test_dry_run(self, conn):
+        result = generate_followups(conn, "VDOL-001", dry_run=True)
+        assert len(result) == 1
+        assert result[0]["_dry_run"] is True
+        assert "followup" in result[0]["_prompt"].lower() or "Previous step output" in result[0]["_prompt"]
+
+    @patch("agents.runner._run_claude")
+    def test_logs_generation(self, mock_claude, conn):
+        mock_claude.return_value = {
+            "output": json.dumps([{"title": "Fix A", "priority": 2}]),
+            "returncode": 0,
+        }
+        generate_followups(conn, "VDOL-001")
+
+        logs = conn.execute(
+            "SELECT * FROM agent_logs WHERE agent_role='followup_pm'"
+        ).fetchall()
+        assert len(logs) == 1
+        assert logs[0]["task_id"] == "VDOL-001"
+
+    @patch("agents.runner._run_claude")
+    def test_prompt_includes_language(self, mock_claude, conn):
+        """Followup prompt should include language instruction."""
+        mock_claude.return_value = {"output": "[]", "returncode": 0}
+        generate_followups(conn, "VDOL-001")
+
+        prompt = mock_claude.call_args[0][0]
+        assert "Russian" in prompt