Set up development environment (deps manifest + AGENTS.md)

[ThyFriendlyFox]

Summary

Sets up the development environment for the Multi-Agent Orchestration System (ORC) so a Cloud Agent (or a new developer) can install dependencies and run the agents.

The repo previously had no dependency manifest, no lockfile, no CI, and no lint/test config. This PR adds the missing pieces without touching any product code.

Changes

• requirements.txt — documents the previously-undeclared dependencies: google-adk + python-dotenv (required by all agents) and gspread + pandas (only for google-sheets-agent).
• AGENTS.md — adds a ## Cursor Cloud specific instructions section covering the key runtime gotcha (every agent needs a valid GOOGLE_API_KEY/Gemini to do anything), first-time setup, how to run the agents, and the fact that there is no build/lint/test framework.

Verification

• Installed google-adk (2.6.3), python-dotenv, gspread, pandas.
• Ran python3 setup_multi_agent.py — created the workspace/ tree and .env.
• All 9 agents import successfully.
• python3 -m compileall passes for all entry points.
• Ran file-agent/run_autonomous.py end-to-end: it starts, loads .env, enters the monitor loop, detects a pending task, and invokes the Gemini metacognition LLM. The only failure is 400 API_KEY_INVALID from a placeholder key — confirming the wiring is correct and a valid GOOGLE_API_KEY is the sole requirement to complete tasks.

Note

.env and workspace/ remain gitignored (runtime-only) and are not committed.