Melee techniques, held guard, dodge, poise and the tactical grid

Make melee active and readable (decision #145): one Melee skill, weapon classes with techniques, telegraphed wind-ups, a held guard with perfect parries, dodges, facing, poise and executions, momentum, knockbacks into the world, mob techniques, the HUD for all of it, and a tile grid in a fight showing obstacles and impassable tiles.

Built: rules, server, protocol, offline and online client, MCP tools (see the fragment and docs/melee.md § 17).

Open: weapon swap, falls from heights, AI dodging out of telegraphs, the Melee 10 masteries, damage types on player armour, an online timeline strip, sounds per class and outcome (task audio), the balance runs of docs/melee.md § 14 with scripted player skill levels, and a playtest wave to tune the windows and numbers.