docs: add Cursor Cloud specific instructions to AGENTS.md

[jgentes]

Description

Add Cursor Cloud specific development instructions to AGENTS.md and fix an out-of-sync lockfile version in the VSCode extension.

Type of Change

• Documentation update

Changes Made

• Added ## Cursor Cloud specific instructions section to AGENTS.md covering services overview, running the MCP server/CLI, testing notes, lint expectations, and VSCode extension dependency management.
• Fixed vscode-extension/package-lock.json version field from stale 1.2.10 to current 1.3.7.

Testing

• Manual testing performed

Test instructions:

1. npm run check — Biome lint/format passes (21 files, no issues)
2. npm run build — TypeScript compilation succeeds
3. npm test — 491/491 tests pass
4. npm run dev — MCP server starts and accepts connections
5. CLI hello world — echo -e "status\nlist\nhelp\nexit" | npx tsx src/cli/index.ts runs successfully

Documentation

• Updated AGENTS.md for cloud agent development context

Checklist

• My code follows the style guidelines of this project (Biome)
• I have performed a self-review of my own code
• My changes generate no new warnings or errors
• New and existing unit tests pass locally with my changes
• I have used conventional commit messages

Screenshots/Logs

Dev server startup:
dev_server_startup.log

CLI hello world:
cli_hello_world.log

Security Considerations

• N/A

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