feat(agents): add AGENTS.md entry point at repo root

Short pointer for agents working directly in this repo.
Points to timesfm-forecasting/SKILL.md and provides
install commands for the first-party Agent Skill.

AGENTS.md

@@ -0,0 +1,36 @@
+# TimesFM — Agent Entry Point
+
+This repository ships a first-party **Agent Skill** for TimesFM at:
+
+```
+timesfm-forecasting/
+└── SKILL.md    ← read this for the full skill
+```
+
+## Install the skill
+
+Copy the skill directory into your agent's skills folder:
+
+```bash
+# Cursor / Claude Code / OpenCode / Codex (global install)
+cp -r timesfm-forecasting/ ~/.cursor/skills/
+cp -r timesfm-forecasting/ ~/.claude/skills/
+
+# Or project-level
+cp -r timesfm-forecasting/ .cursor/skills/
+```
+
+Any agent that supports the open [Agent Skills standard](https://agentskills.io) will discover it automatically.
+
+## Working in this repo
+
+If you are developing TimesFM itself (not using it), the source lives in `src/timesfm/`.
+Archived v1/v2 code and notebooks are in `v1/`.
+
+Run tests:
+
+```bash
+pytest v1/tests/
+```
+
+See `README.md` for full developer setup.