ALL-704 — Create @texturehq/edges-tokens package (new palette)

Spawned Claude Code sub-agent (session brisk-breeze) to scaffold packages/edges-tokens/ per Color Tokens Spec v2. Branch: anvil/all-704-edges-tokens-package. Worktree: /home/agent/agents/mono-edges-tokens. Does NOT modify packages/edges. Follow-up ALL-705 wires apps/styles to consume this package and begins IA migration.