Give the write path a CLI and an MCP face

remember / supersede / forget now reach the one Python writer from a
terminal, from MCP, and from HTTP. The server, not the caller, decides
who owns a memory.

- cli: remember, supersede, forget. --holder falls back to
  settings.default_holder until the holder registry lands. Timestamps are
  parsed once with one clear message.
- ingestion: import pymupdf as fitz. The deprecated fitz import printed a
  warning to stdout, so every CLI command's JSON answer was unparseable.
- mcp: remember, supersede_memory and forget_memory forward to the Python
  writer over HTTP (ELY_EYE_API, default http://127.0.0.1:8765). SQLite
  stays read-only to the Go side, so the write rules live in one place.
- mcp reads follow schema v2: atoms.time became ingested_at, and reads go
  through v_atoms_current, so a superseded memory stops being findable.
  holder, origin, scenario and event_time now show up in fetch_atom and
  search_atoms.
- scripts/mcp_write_smoke.sh proves the loop end to end: remember, search,
  supersede, forget, then not found.

Evidence: 92 pytest passed; go build, go vet and go test clean; mypy clean
on the 10 touched source files with a fresh cache; ruff clean except a
pre-existing B008 at cli.py:292, identical at HEAD.

backend/tests/test_memory_cli.py

@@ -0,0 +1,108 @@
+"""The CLI face of the write path: a person at a terminal can hand a memory to
+a named holder, replace it, and take it back, and every answer is JSON."""
+
+from __future__ import annotations
+
+import json
+from typing import Any
+
+import pytest
+from typer.testing import CliRunner
+
+from ely_eye import cli as cli_module
+from ely_eye.cli import app
+from ely_eye.config import Settings
+from ely_eye.db import Database
+
+runner = CliRunner()
+
+
+@pytest.fixture()
+def db(tmp_path, monkeypatch) -> Database:
+    settings = Settings(home=tmp_path, default_holder="husband")
+    monkeypatch.setattr(cli_module, "get_settings", lambda: settings)
+    return Database(settings)
+
+
+def run(*args: str) -> Any:
+    result = runner.invoke(app, list(args))
+    assert result.exit_code == 0, result.output
+    return json.loads(result.output)
+
+
+def test_remember_stamps_the_default_holder_when_none_is_given(db: Database) -> None:
+    atom = run("remember", "钥匙在玄关抽屉")
+    assert atom["holder_id"] == "husband"
+    assert atom["origin"] == "self"
+    assert atom["source"] == "memory://husband/general"
+    assert db.atom_count() == 1
+
+
+def test_remember_carries_the_holder_scenario_and_event_time(db: Database) -> None:
+    atom = run(
+        "remember",
+        "结婚纪念日是五月一日",
+        "--holder",
+        "wife",
+        "--scenario",
+        "home",
+        "--event-time",
+        "2026-05-01T00:00:00+08:00",
+        "--precision",
+        "day",
+    )
+    assert atom["holder_id"] == "wife"
+    assert atom["scenario"] == "home"
+    assert atom["event_time"].startswith("2026-05-01T00:00:00+08:00")
+    assert atom["event_time_precision"] == "day"
+
+
+def test_remember_refuses_an_event_time_without_an_offset(db: Database) -> None:
+    result = runner.invoke(
+        app,
+        ["remember", "昨天下的雨", "--event-time", "2026-05-01T12:00:00", "--precision", "day"],
+    )
+    assert result.exit_code != 0
+    assert "memory timestamps need an explicit offset" in str(result.exception)
+
+
+def test_remember_refuses_a_malformed_timestamp(db: Database) -> None:
+    result = runner.invoke(app, ["remember", "昨天下的雨", "--event-time", "yesterday"])
+    assert result.exit_code != 0
+    assert "--event-time 'yesterday' is not an ISO timestamp" in str(result.exception)
+
+
+def test_supersede_links_the_replacement_and_closes_the_original(db: Database) -> None:
+    old = run("remember", "钥匙在玄关抽屉", "--holder", "wife")
+    new = run("supersede", old["atom_id"], "钥匙在客厅茶几", "--holder", "wife")
+    assert new["supersedes"] == [old["atom_id"]]
+    assert new["valid_from"] is not None
+    stored = db.get_atoms([old["atom_id"]])[0]
+    assert stored.valid_to is not None
+    assert db.atom_count() == 2
+
+
+def test_supersede_names_the_missing_atom(db: Database) -> None:
+    result = runner.invoke(app, ["supersede", "nope:text", "新的说法"])
+    assert result.exit_code != 0
+    assert "cannot supersede nope:text" in str(result.exception)
+
+
+def test_forget_reports_what_it_removed(db: Database) -> None:
+    atom = run("remember", "钥匙在玄关抽屉", "--holder", "wife")
+    report = run("forget", "--source-id", atom["source_id"], "--reason", "moved house")
+    assert report["atoms_deleted"] == 1
+    assert report["reason"] == "moved house"
+    assert db.atom_count() == 0
+
+
+def test_forget_refuses_to_guess_between_two_ids(db: Database) -> None:
+    result = runner.invoke(app, ["forget", "--atom-id", "a:text", "--source-id", "b"])
+    assert result.exit_code != 0
+    assert "exactly one of atom_id or source_id" in str(result.exception)
+
+
+def test_the_cli_answers_in_json_a_machine_can_read(db: Database) -> None:
+    result = runner.invoke(app, ["remember", "钥匙在玄关抽屉", "--holder", "wife"])
+    assert result.exit_code == 0
+    assert json.loads(result.output)["text"] == "钥匙在玄关抽屉"