docs: Add beads (bd) as prerequisite and move section before Quick Start

- Add beads (bd) to Prerequisites with install link
- Move Prerequisites section before Quick Start for visibility
- Add version requirements: Go 1.23+, Git 2.25+, tmux 3.0+

Fixes gt-1ntmd

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -11,6 +11,14 @@ Multi-agent orchestrator for Claude Code. Track work with convoys; sling to agen
 | 4-10 agents is chaotic | Comfortably scale to 20-30 agents |
 | Work state in agent memory | Work state in Beads (git-backed ledger) |
 
+## Prerequisites
+
+- **Go 1.23+** - [go.dev/dl](https://go.dev/dl/)
+- **Git 2.25+** - for worktree support
+- **beads (bd)** - [github.com/steveyegge/beads](https://github.com/steveyegge/beads) - required for issue tracking
+- **tmux 3.0+** - for full stack mode (optional for minimal mode)
+- **Claude Code CLI** - [claude.ai/code](https://claude.ai/code)
+
 ## Quick Start
 
 ```bash
@@ -260,13 +268,6 @@ Molecules survive crashes - any agent can continue where another left off.
 
 ---
 
-## Prerequisites
-
-- **Go 1.23+**
-- **Git**
-- **tmux** (for full stack mode)
-- **Claude Code CLI**
-
 ## License
 
 MIT