lemon_memory

# Changelog

All notable changes to `lemon_memory` are documented here.
The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/);
releases follow [Semantic Versioning](https://semver.org/) from `0.1.0` onward.

## [Unreleased]

First release. `lemon_memory` is a new package, carved out of `lemon_core`,
where durable memory had been eight modules with no boundary of their own.

### Added

- `LemonMemory.Store` — SQLite-backed document store with full-text search over
  an agent's past work. Queries are sanitised before they reach FTS5, so agent-
  and human-authored queries containing quotes, wildcards or boolean operators
  return results instead of errors.
- `LemonMemory.Provider` — a behaviour for adding memory backends (a vector
  store, a wiki, an issue tracker). The contract is documented in prose in the
  moduledoc, including the parts that are easy to get wrong: `search/2` returns
  a bare list of documents, must not raise on user input, and must ignore
  options it does not recognise.
- `LemonMemory.Providers` — the fan-out registry. Every registered provider is
  queried in a task with a per-provider timeout, and exceptions and exits are
  rescued and logged, so one slow or broken provider degrades a search instead
  of failing it.
- `LemonMemory.Document` as the single record shape every provider reads and
  writes; `LemonMemory.Safety` for redaction and size limits before persistence;
  `LemonMemory.SessionSearch` for scoped search; `LemonMemory.TaskFingerprint`
  for recognising repeated work.
- `LemonMemory.Document.new/1` builds a document from fields directly (for
  callers driving `LemonAgent` themselves), applying the same 2,000-byte summary
  truncation and required-field validation as `from_run/4`. Building the struct
  literally skips both, silently indexing whole transcripts;
  `LemonMemory.Document.max_summary_bytes/0` exposes the cap.
- `LemonMemory.Ingest` writes finished runs into memory by registering itself
  as a `LemonCore.Store` finalize-run hook, rather than being called by name
  from the store's hot path.
- `mix lemon.memory` for inspecting and searching the store from the shell.
- `LemonPlatformTest.ProviderCase` (in the `lemon_platform_test` package)
  verifies a provider against this contract.

### Changed

- Modules were renamed from `LemonCore.Memory*` to `LemonMemory.*`
  (`Document`, `Store`, `Provider`, `Providers`, `Providers.Local`, `Ingest`,
  `Safety`, `SessionSearch`, `TaskFingerprint`), and the application
  environment key moved from `:lemon_core, LemonCore.MemoryStore` to
  `:lemon_memory, LemonMemory.Store`. This was a clean break with no
  compatibility shims; `lemon_core` has no memory references left.
- `:exqlite` is a hard dependency here, not an optional one as in `lemon_core`.
  Supervision reflects that: `Providers` always starts, `Store` and `Ingest`
  start when SQLite is available.
- `Store.get_by_session/2`, `get_by_agent/2` and `get_by_workspace/2` now break
  `ingested_at_ms` ties by `doc_id`, so two documents written in the same
  millisecond come back in a stable order instead of an arbitrary one (a source
  of flaky ordering assertions).

### Known gaps

- `Provider.search/2` has no error channel, so "no results" and "my backend is
  unreachable" are indistinguishable to the platform. Widening it is a
  behaviour change and is deliberately deferred.
- `LemonMemory.Ingest` always registers under its own module name; a `:name`
  option is planned before this API is considered stable.
- `LemonMemory.SessionSearch` has no direct test coverage — its callers cover
  it indirectly.