Reorganize docs and add implementation spec

Move GOAL.md, PRODUCT.md, SPEC.md from repo root into doc/. Add
AGENTS.md (contributor guidance), doc/DEVELOPING.md (dev setup),
doc/SPEC-implementation.md (V1 implementation contract), and
doc/specs/ui.md (UI design spec). Update ClipHub doc.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

doc/GOAL.md

@@ -0,0 +1,47 @@
+# Paperclip
+
+Build software to manage a zero-human company where all employees are AI agents.
+
+## The Problem
+
+Task management software doesn't go far enough. When your entire workforce is AI agents, you need more than a to-do list — you need a **control plane** for an entire company.
+
+## What This Is
+
+Paperclip is the command, communication, and control plane for a company of AI agents. It is the single place where you:
+
+- **Manage agents as employees** — hire, organize, and track who does what
+- **Define org structure** — org charts that agents themselves operate within
+- **Track work in real time** — see at any moment what every agent is working on
+- **Control costs** — token salary budgets per agent, spend tracking, burn rate
+- **Align to goals** — agents see how their work serves the bigger mission
+- **Store company knowledge** — a shared brain for the organization
+
+## Architecture
+
+Two layers:
+
+### 1. Control Plane (this software)
+
+The central nervous system. Manages:
+
+- Agent registry and org chart
+- Task assignment and status
+- Budget and token spend tracking
+- Company knowledge base
+- Goal hierarchy (company → team → agent → task)
+- Heartbeat monitoring — know when agents are alive, idle, or stuck
+
+### 2. Execution Services (adapters)
+
+Agents run externally and report into the control plane. An agent is just Python code that gets kicked off and does work. Adapters connect different execution environments:
+
+- **OpenClaw** — initial adapter target
+- **Heartbeat loop** — simple custom Python that loops, checks in, does work
+- **Others** — any runtime that can call an API
+
+The control plane doesn't run agents. It orchestrates them. Agents run wherever they run and phone home.
+
+## Core Principle
+
+You should be able to look at Paperclip and understand your entire company at a glance — who's doing what, how much it costs, and whether it's working.