chore: initialize EverOS 1.0.0

md-first memory extraction framework for AI agents.

Markdown is the single source of truth; SQLite holds state and LanceDB
provides the rebuildable vector + BM25 + scalar index. The codebase follows
a single-direction DDD layering (entrypoints -> service -> memory -> infra,
with component / core / config cross-cutting) enforced by import-linter.

Engineering surface:
- Coding conventions in .claude/rules/ (path-scoped) and workflows in
  .claude/skills/ (/commit, /new-branch, /pr).
- GitHub Actions CI runs make lint + test + integration; pre-commit mirrors
  the gates locally (ruff, hygiene hooks, gitlint commit-msg).
- Commit messages follow Conventional Commits, enforced by gitlint.
- make lint also enforces datetime two-zone discipline and OpenAPI drift.

tests/unit/test_config/test_settings.py

@@ -0,0 +1,173 @@
+"""Unit tests for Settings loading."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from everos.config import Settings, load_settings
+
+
+@pytest.fixture(autouse=True)
+def _isolate_env(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Strip any EVEROS_* env vars from the host so tests are deterministic."""
+    for key in list(__import__("os").environ):
+        if key.startswith("EVEROS_"):
+            monkeypatch.delenv(key, raising=False)
+    load_settings.cache_clear()
+
+
+def test_load_settings_defaults_from_toml() -> None:
+    s = load_settings()
+    # Values straight out of config/default.toml
+    assert s.memory.root == Path("~/.everos")
+    assert s.memory.timezone == "UTC"
+    assert s.sqlite.journal_mode == "WAL"
+    assert s.sqlite.synchronous == "NORMAL"
+    assert s.sqlite.foreign_keys is True
+    assert s.sqlite.temp_store == "MEMORY"
+    assert s.sqlite.busy_timeout_ms == 5000
+    assert s.sqlite.journal_size_limit_bytes == 64 * 1024 * 1024
+    assert s.sqlite.cache_size_kb == 2048
+    assert s.lancedb.read_consistency_seconds is None
+
+
+def test_env_overrides_toml(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("EVEROS_SQLITE__BUSY_TIMEOUT_MS", "10000")
+    monkeypatch.setenv("EVEROS_SQLITE__JOURNAL_MODE", "DELETE")
+    s = Settings()
+    assert s.sqlite.busy_timeout_ms == 10000
+    assert s.sqlite.journal_mode == "DELETE"
+    # Untouched values stay at TOML defaults.
+    assert s.sqlite.synchronous == "NORMAL"
+
+
+def test_init_args_override_env(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("EVEROS_SQLITE__BUSY_TIMEOUT_MS", "10000")
+    from everos.config.settings import SqliteSettings
+
+    s = Settings(sqlite=SqliteSettings(busy_timeout_ms=99999))
+    assert s.sqlite.busy_timeout_ms == 99999  # init beats env
+
+
+def test_invalid_journal_mode_rejected() -> None:
+    from pydantic import ValidationError
+
+    with pytest.raises(ValidationError):
+        Settings.model_validate({"sqlite": {"journal_mode": "BOGUS"}})
+
+
+def test_negative_busy_timeout_rejected() -> None:
+    from pydantic import ValidationError
+
+    with pytest.raises(ValidationError):
+        Settings.model_validate({"sqlite": {"busy_timeout_ms": -1}})
+
+
+def test_lancedb_read_consistency_optional_float() -> None:
+    s = Settings.model_validate({"lancedb": {"read_consistency_seconds": 5.0}})
+    assert s.lancedb.read_consistency_seconds == 5.0
+    s2 = Settings.model_validate({"lancedb": {"read_consistency_seconds": None}})
+    assert s2.lancedb.read_consistency_seconds is None
+
+
+def test_memory_timezone_overridable_via_env(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("EVEROS_MEMORY__TIMEZONE", "Asia/Shanghai")
+    s = Settings()
+    assert s.memory.timezone == "Asia/Shanghai"
+
+
+def test_memory_timezone_invalid_rejected() -> None:
+    from pydantic import ValidationError
+
+    with pytest.raises(ValidationError, match="invalid timezone"):
+        Settings.model_validate({"memory": {"timezone": "Not/A/Real_Zone"}})
+
+
+def test_load_settings_is_cached() -> None:
+    """Repeated calls return the same Settings object until cache_clear."""
+    a = load_settings()
+    b = load_settings()
+    assert a is b
+    load_settings.cache_clear()
+    c = load_settings()
+    assert c is not a
+
+
+def test_embedding_rerank_defaults() -> None:
+    """Embedding / rerank ship with runtime knobs but no model credentials."""
+    # ``_isolate_env`` already strips shell env; ``_env_file=None`` further
+    # prevents a developer's ``.env`` (which typically sets MODEL / API_KEY /
+    # BASE_URL for live runs) from leaking into this default-state check.
+    s = Settings(_env_file=None)  # type: ignore[call-arg]
+    # Credentials must be set explicitly (no default).
+    assert s.embedding.model is None
+    assert s.embedding.api_key is None
+    assert s.embedding.base_url is None
+    # Runtime knobs come from default.toml.
+    assert s.embedding.timeout_seconds == 30.0
+    assert s.embedding.max_retries == 3
+    assert s.embedding.batch_size == 10
+    assert s.embedding.max_concurrent == 5
+    # Rerank mirrors the shape.
+    assert s.rerank.model is None
+    assert s.rerank.timeout_seconds == 30.0
+    assert s.rerank.batch_size == 10
+
+
+def test_embedding_env_overrides(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("EVEROS_EMBEDDING__MODEL", "intfloat/e5-large-v2")
+    monkeypatch.setenv("EVEROS_EMBEDDING__BASE_URL", "http://localhost:8000/v1")
+    monkeypatch.setenv("EVEROS_EMBEDDING__BATCH_SIZE", "32")
+    s = Settings()
+    assert s.embedding.model == "intfloat/e5-large-v2"
+    assert s.embedding.base_url == "http://localhost:8000/v1"
+    assert s.embedding.batch_size == 32
+
+
+def test_rerank_env_overrides(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("EVEROS_RERANK__MODEL", "BAAI/bge-reranker-v2-m3")
+    monkeypatch.setenv("EVEROS_RERANK__MAX_CONCURRENT", "8")
+    s = Settings()
+    assert s.rerank.model == "BAAI/bge-reranker-v2-m3"
+    assert s.rerank.max_concurrent == 8
+
+
+def test_user_toml_override_via_env_path(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    """``EVEROS_CONFIG_FILE`` points pydantic-settings at a user toml."""
+    user_toml = tmp_path / "config.toml"
+    user_toml.write_text(
+        '[sqlite]\nbusy_timeout_ms = 7777\n[memory]\ntimezone = "Asia/Tokyo"\n',
+        encoding="utf-8",
+    )
+    monkeypatch.setenv("EVEROS_CONFIG_FILE", str(user_toml))
+    s = Settings()
+    assert s.sqlite.busy_timeout_ms == 7777
+    assert s.memory.timezone == "Asia/Tokyo"
+    # Values not touched by the user toml still come from the shipped default.
+    assert s.sqlite.journal_mode == "WAL"
+
+
+def test_user_toml_loses_to_env(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    """env vars beat the user-level toml."""
+    user_toml = tmp_path / "config.toml"
+    user_toml.write_text("[sqlite]\nbusy_timeout_ms = 7777\n", encoding="utf-8")
+    monkeypatch.setenv("EVEROS_CONFIG_FILE", str(user_toml))
+    monkeypatch.setenv("EVEROS_SQLITE__BUSY_TIMEOUT_MS", "9999")
+    s = Settings()
+    assert s.sqlite.busy_timeout_ms == 9999
+
+
+def test_user_toml_missing_file_is_skipped(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
+) -> None:
+    """A non-existent user toml path is silently skipped, not an error."""
+    monkeypatch.setenv("EVEROS_CONFIG_FILE", str(tmp_path / "nope.toml"))
+    s = Settings()
+    # Falls back to shipped defaults.
+    assert s.sqlite.busy_timeout_ms == 5000