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.

src/everos/infra/persistence/lancedb/tables/episode.py

@@ -0,0 +1,78 @@
+"""LanceDB ``episode`` table schema.
+
+Field set is fixed by the LanceDB tables design spec. Rows are populated
+by the cascade daemon from ``users/<owner_id>/episodes/episode-<YYYY-MM-DD>.md``
+and from ``agents/<owner_id>/episodes/...`` symmetrically.
+"""
+
+from __future__ import annotations
+
+import datetime as _dt
+from typing import ClassVar
+
+from everos.core.persistence.lancedb import BaseLanceTable, Vector
+
+from ._parent_type import ParentType
+
+# Vector dimension is settings-managed at runtime; the class-level
+# constant pins the schema dim used at table creation.
+_DIM = 1024
+
+
+class Episode(BaseLanceTable):
+    """One episode record indexed in LanceDB."""
+
+    TABLE_NAME: ClassVar[str] = "episode"
+    BM25_FIELDS: ClassVar[list[str]] = ["episode_tokens"]
+
+    id: str
+    """PK = ``<owner_id>_<entry_id>`` (scalar PK)."""
+
+    entry_id: str
+    """md-side seq id ``ep_<YYYYMMDD>_<NNNN>`` (cascade reverse-lookup)."""
+
+    owner_id: str
+    owner_type: str
+    app_id: str = "default"
+    project_id: str = "default"
+    """App / project scope (default ``"default"``); cascade fills from md path."""
+    session_id: str
+    timestamp: _dt.datetime
+
+    parent_type: str = ParentType.MEMCELL.value
+    """Source pointer — always :attr:`ParentType.MEMCELL` for episode."""
+
+    parent_id: str
+    """Source memcell id. The pipeline knows the memcell currently being
+    processed and writes its id into the md entry's inline block; the
+    cascade handler reads it back. The new everalgo Episode type no
+    longer emits ``parent_id`` itself (collapsed to caller-managed),
+    so this is filled entirely from everos's engineering context."""
+
+    sender_ids: list[str]
+    """Distinct ``role=user|assistant`` senders behind the episode."""
+
+    subject: str | None = None
+    summary: str | None = None
+    episode: str
+    """Full narrative text — original surface form (returned for display)."""
+
+    episode_tokens: str
+    """App-layer pre-tokenised ``episode`` text — space-joined tokens
+    (e.g. produced by jieba). LanceDB FTS index is built on **this**
+    column using a whitespace tokenizer; the original ``episode`` field
+    is what callers display. Two-field BM25 scheme keeps tokenisation
+    deterministic and provider-pluggable at the app layer."""
+
+    md_path: str
+    content_sha256: str
+    """SHA-256 hex digest over the **content-bearing fields only** of the
+    md entry (per :attr:`EpisodeHandler.content_change_keys`). On
+    re-reconcile, a matching digest means none of the persistence /
+    embedding-relevant fields changed — the entry is skipped (no
+    re-upsert, no re-embed). Inline audit fields (owner_id /
+    session_id / timestamp / parent_id / sender_ids) are intentionally
+    NOT in the hash so editing them doesn't waste an embedding call.
+    See ``16_cascade_impl_design.md`` §3.3."""
+
+    vector: Vector(_DIM)  # type: ignore[valid-type]