feat(storage-plugin): add storage-level JSON import/export

[burczu]

Closes #247.

Summary

• Adds Import and Export buttons to the storage panel toolbar, scoped to the currently selected storage.
• Defines a stable, versioned (version: 1) JSON snapshot format with plugin, createdAt, source storage metadata, and typed entries[].
• Hand-written parseSnapshot with path-precise errors (e.g. entries[3].value: Expected finite number…). No new runtime deps.
• Import is an upsert with validate-before-write: any unsupported type aborts before any writes. The preview shows new / overwrite / skipped (blacklisted) counts and warns when the file's source storage differs from the target.
• Runtime delivers a new import-entries event; emits a set-entry echo per successful write so the table updates row by row, then a single import-result for completion. Stops at the first failed write and reports the offending key.
• Extends the snapshot wire format with an optional serialized blacklist (RegExp source/flags) so the panel can compute skip counts against the runtime's filter.
• Docs: new Import / Export section in the storage plugin docs covering behavior, schema, cross-adapter compatibility, and versioning. Pointer added to the package README.
• Changeset: minor bump for @rozenite/storage-plugin.

Test plan

Automated:

• Snapshot parser unit tests — happy paths, every rejection branch, path precision (packages/storage-plugin/src/shared/__tests__/snapshot.test.ts).
• computePreview pure-function tests — bucket priority, blacklist skip, unsupported types, metadata mismatch.
• Runtime bulk handler tests — per-write echo, stop-on-first-error, unknown target, empty entries (packages/storage-plugin/src/react-native/__tests__/import.test.ts).
• pnpm --filter @rozenite/storage-plugin test — 48/48 passing.
• pnpm --filter @rozenite/storage-plugin typecheck — clean.
• pnpm --filter @rozenite/storage-plugin lint — 0 errors (1 pre-existing unrelated warning).
• pnpm --filter @rozenite/docs build — website builds; new section renders.

Manual (playground, MMKV / AsyncStorage / SecureStore via apps/playground):

• Export downloads a valid JSON file named rozenite-storage-<adapter>-<storage>-YYYYMMDD-HHmmss.json.
• Importing an exported file (unchanged) is a no-op preview that applies cleanly.
• Importing a file with version: 2 is rejected with a path-pointed error.
• Importing into an adapter that doesn't support a present type (e.g. buffer into AsyncStorage) disables Apply and lists offenders.
• Importing from a different storage source triggers the metadata-mismatch warning banner.
• Importing an empty entries: [] file applies as a no-op.
• Importing valid edits updates the table row by row as writes land.

Out of scope

• Global cross-storage export.
• replace-all / clear-storage semantics during import.
• Adapter-specific native dump formats.
• Surfacing storages that use shouldFilterKey (function form) — only the blacklist RegExp form is exposed to the UI today.

[V3RON]

Is there a specific reason for handling imports like this instead of sending a batch of set-entry commands from the DevTools UI side?

[burczu]

client.send is fire-and-forget — no per-message ack. With N × set-entry, the UI knows it dispatched N messages but never learns whether the writes landed or where they failed, which makes the issue's "stop on first error" and the modal's "Imported 47/50, failed at userToken" outcome impossible to honor.

import-entries + import-result puts the loop, the stop-on-first-error rule, and the final { ok, written, total, failedKey, error } payload in one place. Per-write set-entry echoes still flow back, so the table updates row by row through the existing snapshot path.

Wire cost is two small event types, both unit-tested. Happy to switch if you'd rather accept silent partial failures.