fix(db): share sql.js preinit across callers, fix named-param bind (#6628, #6802) (#6899)

- preInitSqlJs() now memoizes an in-flight Promise (not just the resolved
  adapter) per filePath, so concurrent BATCH/STARTUP/HealthCheck/
  ProviderLimitsSync callers at boot share one full-file read+WASM decode
  instead of each independently reloading the whole database — the
  thundering-herd amplifier of the OOM condition #6632 already partly
  fixed, left un-implemented by the reporter's own proposed fix (#6628).

- sqljsAdapter's run/get/all now unwrap a lone named-parameter object
  (e.g. .all({ isActive: 1 }) for "WHERE is_active = @isActive", the same
  call shape getProviderConnections() already uses against better-sqlite3)
  before calling sql.js's stmt.bind(), expanding it to the @/:/$ sigil
  variants sql.js's own named-bind path requires. Previously the object
  was wrapped into an array and sql.js took the positional-bind path,
  throwing "Wrong API use : tried to bind a value of an unknown type
  ([object Object])." whenever the sql.js WASM fallback driver was active
  — exactly the error #6802 reported (misattributed to better-sqlite3).

Regression tests added to tests/unit/db-adapters/driverFactory.test.ts and
tests/unit/db-adapters/sqljsAdapter.test.ts, both proven RED against the
prior code and GREEN after the fix.

src/types/sqljs.d.ts

@@ -1,6 +1,6 @@
 declare module "sql.js" {
   export interface SqlJsStatement {
-    bind(values: unknown[]): void;
+    bind(values: unknown[] | Record<string, unknown>): void;
     step(): boolean;
     getAsObject(): Record<string, unknown>;
     free(): void;