feat(REQ-014): add portfolio-create-user-required requirement and implementation

- Add docs/srs/Interface/req-014_portfolio-create-user-required.md with acceptance criteria
- Create docs/batches/bat-004_20260502_portfolio-create-user-required/ delivery batch
- Enhance app/cli/commands/portfolio.py: validate user_id parameter before portfolio creation
- Add comprehensive CLI tests in tests/test_cli.py for portfolio create validation flows
- Update docs/batches/index.md and docs/srs/index.md with new requirement/batch references
- Update README.md documentation

tests/test_cli.py

@@ -485,6 +485,7 @@ def test_cli_status_supports_json_output() -> None:
 
 def test_cli_create_buy_and_delete_flow() -> None:
     repo = FakeRepo()
+    user = repo.create_user("alice", permission="read")
     runner = build_runner(repo)
 
     create_result = runner.invoke(
@@ -495,6 +496,8 @@ def test_cli_create_buy_and_delete_flow() -> None:
             "005930:tv",
             "--symbol",
             "005930",
+            "--user",
+            "alice",
             "--cash-balance",
             "1000000",
             "--strategy-params",
@@ -518,6 +521,7 @@ def test_cli_create_buy_and_delete_flow() -> None:
         ],
     )
     assert repo.entries[0].action == "BUY"
+    assert repo._portfolio.owner_user_id == user.id
     delete_result = runner.invoke(runner.app, ["portfolio", "delete", "005930:tv", "--keep-ledger", "--force"])
 
     assert create_result.exit_code == 0
@@ -528,6 +532,7 @@ def test_cli_create_buy_and_delete_flow() -> None:
 
 def test_cli_write_command_prompts_before_create() -> None:
     repo = FakeRepo()
+    repo.create_user("alice", permission="read")
     runner = build_runner(repo)
 
     result = runner.invoke(
@@ -538,6 +543,8 @@ def test_cli_write_command_prompts_before_create() -> None:
             "005930:tv",
             "--symbol",
             "005930",
+            "--user",
+            "alice",
             "--cash-balance",
             "1000000",
         ],
@@ -550,6 +557,7 @@ def test_cli_write_command_prompts_before_create() -> None:
 
 def test_cli_write_command_can_abort() -> None:
     repo = FakeRepo()
+    repo.create_user("alice", permission="read")
     runner = build_runner(repo)
 
     result = runner.invoke(
@@ -560,6 +568,8 @@ def test_cli_write_command_can_abort() -> None:
             "005930:tv",
             "--symbol",
             "005930",
+            "--user",
+            "alice",
             "--cash-balance",
             "1000000",
         ],
@@ -570,6 +580,47 @@ def test_cli_write_command_can_abort() -> None:
     assert repo._portfolio is None
 
 
+def test_cli_portfolio_create_without_user_exits_error() -> None:
+    repo = FakeRepo()
+    runner = build_runner(repo)
+
+    result = runner.invoke(
+        runner.app,
+        ["portfolio", "create", "005930:tv", "--symbol", "005930", "--force"],
+    )
+
+    assert result.exit_code == 1
+    assert "--user" in result.stdout
+
+
+def test_cli_portfolio_create_with_valid_user_sets_owner() -> None:
+    repo = FakeRepo()
+    user = repo.create_user("alice", permission="read")
+    runner = build_runner(repo)
+
+    result = runner.invoke(
+        runner.app,
+        ["portfolio", "create", "005930:tv", "--symbol", "005930", "--user", "alice", "--force"],
+    )
+
+    assert result.exit_code == 0
+    assert repo._portfolio is not None
+    assert repo._portfolio.owner_user_id == user.id
+
+
+def test_cli_portfolio_create_with_unknown_user_exits_error() -> None:
+    repo = FakeRepo()
+    runner = build_runner(repo)
+
+    result = runner.invoke(
+        runner.app,
+        ["portfolio", "create", "005930:tv", "--symbol", "005930", "--user", "nobody", "--force"],
+    )
+
+    assert result.exit_code == 1
+    assert "nobody" in result.stdout
+
+
 def test_cli_health_check_reports_repository() -> None:
     repo = FakeRepo(_portfolio())
     runner = build_runner(repo)