feat: Nearshore-Ratio indicator per project

Engine (packages/engine):
- calculateShoringRatio() pure function: onshore/offshore hours,
  country breakdown, threshold check, weighted by hours not headcount
- 12 unit tests: empty, 100% onshore/offshore, mixed ratios,
  custom threshold, case-insensitive, unknown country, FTE weighting

Schema:
- Project.shoringThreshold (default 55%) — per-project configurable
- Project.onshoreCountryCode (default "DE") — configurable onshore country

API (project router):
- getShoringRatio query: loads assignments with resource.country,
  computes ratio, returns full breakdown
- update mutation: accepts shoringThreshold + onshoreCountryCode

UI:
- ShoringIndicator: stacked horizontal bar with country segments,
  severity badge (green/yellow/red), hover tooltip, dark theme
- ShoringBadge: mini colored dot + % for project list column
- ProjectModal: "Max Offshore %" number input
- Project detail: indicator after budget status card
- Project list: "Shoring" column (default hidden, toggleable)

AI Assistant:
- get_shoring_ratio tool: human-readable breakdown with threshold alert

Colors: green (<threshold-10), yellow (threshold-10 to threshold), red (>=threshold)
Default: 55% offshore threshold, "DE" as onshore country

Co-Authored-By: claude-flow <ruv@ruv.net>

packages/shared/src/constants/columns.ts

@@ -21,6 +21,7 @@ export const PROJECT_COLUMNS: ColumnDef[] = [
   { key: "dates",       label: "Dates",       defaultVisible: true,  hideable: true  },
   { key: "budget",      label: "Budget",      defaultVisible: false, hideable: true  },
   { key: "allocations", label: "Allocations", defaultVisible: true,  hideable: true  },
+  { key: "shoring",     label: "Shoring",     defaultVisible: false, hideable: true  },
   { key: "responsible", label: "Responsible", defaultVisible: false, hideable: true  },
 ];