docs: ROADMAP full restore + #98-143 tech debt links + archive historical DESIGN/CHANGES (#144)

docs/archive/CHANGES-0.18.0-phase1.md

@@ -0,0 +1,99 @@
+# v0.18.0 Phase 1 — Changes Guide
+
+## New Files (drop in place)
+
+| File | Description |
+|------|-------------|
+| `server/database/migrations/004_v0180_memories.sql` | Postgres migration — memories table, indexes, trigger |
+| `server/database/migrations/sqlite/003_v0180_memories.sql` | SQLite equivalent |
+| `server/models/models_memory.go` | Memory + MemoryFilter model structs + scope/status constants |
+| `server/store/store_memory.go` | MemoryStore interface definition |
+| `server/store/postgres/memory.go` | Postgres MemoryStore implementation |
+| `server/store/sqlite/memory.go` | SQLite MemoryStore implementation |
+| `server/tools/memory.go` | memory_save + memory_recall tools with late registration |
+| `server/handlers/memory_inject.go` | BuildMemoryHint() for context injection |
+| `docs/DESIGN-0.18.0.md` | Design document |
+
+## Existing File Modifications
+
+### 1. `server/store/interfaces.go`
+
+Add to the `Stores` struct (after `ResourceGrants`):
+
+```go
+Memories       MemoryStore
+```
+
+The `MemoryStore` interface itself is in the new `store_memory.go` file
+(same package, separate file for cleanliness).
+
+### 2. `server/store/postgres/stores.go`
+
+Add to the `NewStores()` return:
+
+```go
+Memories:       NewMemoryStore(),
+```
+
+### 3. `server/store/sqlite/stores.go`
+
+Add to the `NewStores()` return:
+
+```go
+Memories:       NewMemoryStore(),
+```
+
+### 4. `server/main.go`
+
+Add after the existing tool registrations (~line 169):
+
+```go
+// Memory tools (v0.18.0) — late registration, needs stores
+tools.RegisterMemoryTools(stores)
+```
+
+### 5. `server/handlers/completion.go`
+
+In `loadConversation()`, add memory injection after the KB hint block
+(~line 798, after the `BuildKBHint` block):
+
+```go
+// ── Memory injection (recall known facts about user) ──
+if memHint := BuildMemoryHint(context.Background(), h.stores, userID, personaID); memHint != \"\" {
+    messages = append(messages, providers.Message{
+        Role:    \"system\",
+        Content: memHint,
+    })
+}
+```
+
+### 6. `VERSION`
+
+```
+0.18.0
+```
+
+### 7. `docs/ROADMAP.md`
+
+Mark Phase 1 items as complete (Data Model, Tools, Memory Injection basics).
+
+---
+
+## Testing Checklist
+
+1. **Migration runs clean** — both Postgres and SQLite
+2. **Tools register** — check startup logs for `🔧 Registered tool: memory_save` and `memory_recall`
+3. **memory_save** — in a chat, tell the AI something personal (\"I prefer Go over Python\"). The AI should call memory_save.
+4. **memory_recall** — in a NEW chat, ask \"what programming language do I prefer?\" The AI should call memory_recall and find it.
+5. **Persona scoping** — with a Persona active, memories save as `persona_user` scope. Without a Persona, they save as `user` scope.
+6. **Upsert** — saving the same key twice updates the value instead of creating a duplicate.
+7. **Injection** — memories appear in the system prompt context (check server logs for `🧠 Injected N memories`).
+
+## Architecture Notes
+
+- Memory injection happens in `loadConversation()` as a system message, same pattern as KB hints and compaction summaries
+- Scope priority in Recall: persona_user > persona > user (most specific wins)
+- The unique index on `(scope, owner_id, COALESCE(user_id, nil_uuid), key)` prevents duplicate keys within a scope
+- Confidence is LLM-provided: 1.0 for explicit statements, lower for inferences
+- Status field supports Phase 2's review pipeline (pending_review, archived)
+- Embedding column exists but is unused in Phase 1 — Phase 2 adds semantic recall