feat(memory): create MempalaceAdapter implementing MemoryManager interface [phase-5]

[quangdang46]

Problem

jcode's MemoryManager is a concrete struct (~1800 lines) used at ~12 call sites across 7 crates. To integrate mempalace as a backend, we need an adapter that maps MemoryManager API → mempalace MemoryProvider trait, without changing all call sites at once.

There is currently no trait separating storage from logic — MemoryManager directly loads/saves MemoryGraph JSON files.

Scope

Files: New crate crates/jcode-mempalace-adapter/ (or new module in crates/jcode-base/src/memory/)

1. Create MempalaceAdapter:

   pub struct MempalaceAdapter {
       palace: mempalace_core::palace::Palace,
       sidecar: Option<jcode_base::sidecar::Sidecar>,
   }

2. Implement all MemoryManager public methods by delegating to Palace:

   MemoryManager method	MempalaceAdapter → Palace call
   remember_project(entry)	add_drawer(entry.into_drawer()) with scope=Local
   remember_global(entry)	add_drawer(entry.into_drawer()) with scope=Global
   find_similar(query, threshold, max)	search_with_embedding(query_vec, scope)
   find_similar_with_cascade(...)	cascade_search (mempalace [#15b] Extension compatibility lane: global + per-extension forced-compat with reason codes #31)
   search_scoped(query, scope)	search(query, scope.into())
   tag_memory(id, tag)	tag(id, tag)
   link_memories(from, to, w)	link(from, to, w)
   forget(id)	forget(id)
   get_prompt_memories_scoped(limit, scope)	recent(limit, scope.into())
   get_related(id, depth)	related(id, depth)
   graph_stats()	graph_stats_legacy() → (memories, tags, edges, clusters)
   list_all_scoped(scope)	get_drawers(Some(scope.into()), None)
   backfill_embeddings()	iterate get_drawers(), embed, upsert

3. Type conversions:

   • MemoryEntry → Drawer (and back): map category→kind, scope, confidence, strength, timestamps, embeddings
   • MemoryCategory → DrawerKind: Fact→Fact, Preference→Preference, Entity→Entity, Correction→Correction, Custom(s)→Custom(s)
   • MemoryScope → mempalace::MemoryScope: Project→Local, Global→Global, All→All

4. Constructor:

   impl MempalaceAdapter {
       pub async fn new(palace_path: &Path, project_dir: Option<&Path>) -> anyhow::Result<Self>
   }

   Uses PalaceBuilder to construct a Palace pointing at the given path.

5. Feature flag: #[cfg(feature = "mempalace-backend")] gates the adapter crate.

Acceptance Criteria

• All MemoryManager methods delegate correctly to Palace
• Type conversions (MemoryEntry↔Drawer, MemoryCategory↔DrawerKind) are lossless
• Existing jcode unit tests pass when adapter is used behind feature flag
• Adapter compiles without requiring changes to MemoryManager callers
• cargo test -p jcode-mempalace-adapter passes

Dependencies

mempalace issues (must be resolved first):

• /share: upload exported session HTML as a private GitHub gist and copy the link #25 (timestamps)
• /scoped-models + Ctrl+P / Shift+Ctrl+P: cycle models within a user-defined allowlist #26 (confidence/strength)
• [#3b] Extension hostcall hardening: secret-aware env filter, hostcall taxonomy, preflight static analysis #28 (DrawerKind alignment)
• [#15a] Extension trust state machine: pending/acknowledged/trusted/killed + lift + reason codes #30 (memory_score)
• [#15b] Extension compatibility lane: global + per-extension forced-compat with reason codes #31 (cascade retrieval)
• [#3a] Extension runtime: embedded QuickJS, manifest, capability declarations #27 (typed edges)

Reference

jcode MemoryManager: crates/jcode-base/src/memory.rs lines 148-1846
jcode MemoryEntry: crates/jcode-memory-types/src/lib.rs lines 233-266
mempalace MemoryProvider trait: crates/core/src/palace.rs lines 702+
mempalace Palace struct: crates/core/src/palace.rs line 1225+

[quangdang46]

Closed — implemented in PR #364 (merged). MempalaceAdapter with bidirectional type conversions in + .