Two zone fixes.
helper-manager: the contextual HUD only rendered for tools with `def.toolHints`,
so zone (none) showed no HUD and no snapping chip even though it resolves a snap
context. Render the generic RegisteredToolHelper whenever the tool has hints OR a
snap/continuation context; hoist the legacy `roof` RoofHelper above it so the new
fallback doesn't capture it. Any snappable hint-less draft tool now advertises
Shift = cycle.
zone-tool: a not-yet-migrated legacy tool — it used Shift as a snap bypass and
applied `gridSnapStep` unconditionally, so Off mode still snapped to grid.
Migrated to the mode-driven exclusive-modes convention (zone resolves to the
'wall' context): grid quantize gated on isGridSnapActive(), 15° ray gated on
isAngleSnapActive(), Off/Lines leave the raw cursor. Dropped the Shift-bypass and
its key listeners — Shift now cycles the mode globally. Recorded as migrated in
the review skill's known-legacy list.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
