feat(tools,docs): add full export and list API helpers for memories (#1653)

[Adityakk9031]

Summary

Resolves #1653

This PR introduces comprehensive listing, exhaustive pagination, and export tools for distilled memories (memory entries) across both self-hosted and cloud Supermemory deployments:

1. Memory Export & Pagination Utilities (@supermemory/tools):
   • Added listMemoriesRequest: Direct caller for the /v4/memories/list endpoint with container tags, pagination, and sorting.
   • Added fetchAllMemories: Auto-paginating helper that iterates through all pages to retrieve all memory entries for a container tag.
   • Added exportMemoriesAsJson: Full JSON backup serializer with metadata (exportedAt, totalCount, containerTag, baseUrl).
   • Added exportMemoriesAsMarkdown: Human-readable Markdown export format with revision histories and source document references.
2. CLI Tool (supermemory-export):
   • Added supermemory-export CLI in @supermemory/tools/bin for terminal-based backups (bunx @supermemory/tools supermemory-export --tag user_123 --out backup.json --url http://localhost:6767).
3. Self-Hosting Documentation:
   • Added a dedicated Backup & Export Guide documenting:
     • The distinction between raw ingested documents (/v3/documents) and extracted memory cards (/v4/memories/list).
     • Why direct disk copying of encrypted local storage (.supermemory/data SMD1 format) is unsupported and how the HTTP API provides a clean, portable backup path.
     • Complete, copy-pasteable export scripts in cURL, Python, TypeScript, and via the CLI.
     • Memory migration guide from self-hosted to cloud platform (POST /v4/memories).
   • Linked from apps/docs/docs.json under Deployment > Supermemory local, and apps/docs/self-hosting/overview.mdx.
4. Unit Tests:
   • Added 6 unit tests in packages/tools/src/export-memories.test.ts validating request formation, pagination, soft-forgotten memory filtering, and JSON/Markdown outputs.

Testing

• Ran bun test src/export-memories.test.ts (6 passing).
• Ran bun test src/tools-shared.test.ts src/export-memories.test.ts (19 passing).
• Verified bun run ./bin/supermemory-export.ts --help runs and outputs correct usage.