QMD SDK Migration — Phase 1+2: DB init via createStore() + kill deep imports

[ashu17706]

What

Replace smriti's manual DB setup and deep QMD imports with the stable public SDK.

Phase 1 — DB init via createStore()

Currently initSmriti() manually opens the SQLite database, calls loadSqliteVec(), and runs QMD table setup. Replace with:

```ts
const store = await createStore({ dbPath: QMD_DB_PATH });
// store.internal.db is now the shared Database handle
// QMD handles its own table init and sqlite-vec loading
runSmritiMigrations(store.internal.db);
```

Files: src/db.ts, src/index.ts

Phase 2 — Kill deep imports in memory.ts

Replace every ../qmd/src/ import with InternalStore equivalents:

Current	Replacement
insertEmbedding(db, ...)	store.insertEmbedding(...)
Manual CREATE VIRTUAL TABLE vectors_vec	store.ensureVecTable(dimensions)
getDefaultLlamaCpp() + manual embed loop	store.internal.llm
chunkDocumentByTokens()	move to smriti util or keep as single import
reciprocalRankFusion()	keep as single import (not on InternalStore)
hashContent()	replace with Bun.CryptoHasher (SHA256, 3 lines)

Files: src/memory.ts

After this: src/memory.ts has zero ../qmd/src/ deep imports.

Why

Deep imports into ../qmd/src/store.js and ../qmd/src/llm.js break silently on any upstream QMD refactor. Every upstream sync is a potential breakage point. The public InternalStore API is stable and intentional.

Acceptance Criteria

• src/db.ts uses createStore() for DB init — no manual loadSqliteVec()
• src/memory.ts has no imports from ../qmd/src/
• All existing tests pass (no behavior change)
• smriti status, smriti recall, smriti ingest work correctly

[ashu17706]

Implemented and committed on the dev branch.