feat(core): introduce opaque storage adapters

[Egge21M]

Summary

• replace direct repository-bag injection with an opaque CocoStorage contract in core
• add an adapter-only internal storage entrypoint so adapters can still access repositories and transactions without exposing them through the app-facing API
• migrate coco-cashu-sqlite-bun and related tests/docs to the new storage-based initialization flow

Why

The framework is intended to be used through Manager and the public APIs it exposes. Previously, consumers had easy access to individual repositories because storage adapters surfaced the full repository bag directly. This change narrows the public boundary while still preserving a supported path for adapter authors.

What Changed

• added an internal storage adapter boundary in packages/core
• kept root CocoStorage minimal and app-facing
• moved internal adapter access behind the adapter-only subpath
• removed remaining direct repository plumbing from Manager
• updated watcher bootstrapping to go through services
• migrated sqlite-bun as the proof-of-concept adapter
• updated docs and examples from repo to storage

Follow-ups

• migrate sqlite3, indexeddb, and expo-sqlite to the same internal storage adapter pattern

[changeset-bot]

⚠️ No Changeset found

Latest commit: 2811de8

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR