feat: add listMemories tool to MCP server

[Nemskri]

What does this PR do?

This PR implements the requested listMemories tool for the Supermemory Model Context Protocol (MCP) server, addressing Issue #1030. This allows AI assistants (like Claude) to enumerate and audit stored memories in a paginated/sortable list instead of only retrieving them via semantic recall.

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Implementation Details

1. MCP Tool Registration (apps/mcp/src/server.ts):

   • Registered the listMemories tool.
   • Defined Zod schemas for limit (max 200), cursor (opaque token for pages), sort (created_desc, created_asc, updated_desc), filter (optional search substring), and optional project containerTag.

2. SDK client helper (apps/mcp/src/client.ts):

   • Added listMemories helper method to the SupermemoryClient.
   • Queries this.client.documents.list under the hood (per the SDK v4 design where /v3/documents/list returns the list of memories).
   • Applies local case-insensitive substring filter matching on titles and text.

3. Standard Transport Fix (apps/mcp/src/index.ts):

   • Set the default server transport to "sse" in SupermemoryMCP.serve(...).
   • This resolves a 400 Bad Request connection error when standard SSE clients (like the official MCP Inspector) try to connect without a pre-initialized session ID header.

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Verification & Testing

• Type Checking: Verified that the type check passes on the mcp app target with bunx tsc --noEmit --project apps/mcp/tsconfig.json.
• Formatting: Ran npx biome check on modified files to ensure strict compliance with code formatting/linting rules (all checks passed).
• Manual verification: Connected successfully via the official MCP Inspector using standard SSE at http://localhost:8788/mcp and verified that the schema parameters show up correctly and run under local mock authentications.