feat: add Future Year Budget Planning with inflation-adjusted projections

Adds budget planning capability under Board Planning, allowing HOA boards
to model future year budgets with configurable per-year inflation rates.

Backend:
- New budget_plans + budget_plan_lines tables (migration 014)
- BudgetPlanningService: CRUD, inflation generation (per-month preservation),
  status workflow (planning → approved → ratified), ratify-to-official copy
- 8 new API endpoints on board-planning controller
- Projection engine (both board-planning and reports) now falls back to
  planned budgets via UNION ALL query when no official budget exists
- Extended year range from 3 to dynamic based on projection months

Frontend:
- BudgetPlanningPage with monthly grid table (mirrors BudgetsPage pattern)
- Year selector, inflation rate control, status progression buttons
- Inline editing with save, confirmation modals for status changes
- Manual edit tracking with visual indicator
- Summary cards for income/expense totals

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/modules/board-planning/board-planning.controller.ts

@@ -4,6 +4,7 @@ import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
 import { AllowViewer } from '../../common/decorators/allow-viewer.decorator';
 import { BoardPlanningService } from './board-planning.service';
 import { BoardPlanningProjectionService } from './board-planning-projection.service';
+import { BudgetPlanningService } from './budget-planning.service';
 
 @ApiTags('board-planning')
 @Controller('board-planning')
@@ -13,6 +14,7 @@ export class BoardPlanningController {
   constructor(
     private service: BoardPlanningService,
     private projection: BoardPlanningProjectionService,
+    private budgetPlanning: BudgetPlanningService,
   ) {}
 
   // ── Scenarios ──
@@ -127,4 +129,49 @@ export class BoardPlanningController {
   ) {
     return this.service.executeInvestment(id, dto.executionDate, req.user.sub);
   }
+
+  // ── Budget Planning ──
+
+  @Get('budget-plans')
+  @AllowViewer()
+  listBudgetPlans() {
+    return this.budgetPlanning.listPlans();
+  }
+
+  @Get('budget-plans/available-years')
+  @AllowViewer()
+  getAvailableYears() {
+    return this.budgetPlanning.getAvailableYears();
+  }
+
+  @Get('budget-plans/:year')
+  @AllowViewer()
+  getBudgetPlan(@Param('year') year: string) {
+    return this.budgetPlanning.getPlan(parseInt(year, 10));
+  }
+
+  @Post('budget-plans')
+  createBudgetPlan(@Body() dto: { fiscalYear: number; baseYear: number; inflationRate?: number }, @Req() req: any) {
+    return this.budgetPlanning.createPlan(dto.fiscalYear, dto.baseYear, dto.inflationRate ?? 2.5, req.user.sub);
+  }
+
+  @Put('budget-plans/:year/lines')
+  updateBudgetPlanLines(@Param('year') year: string, @Body() dto: { planId: string; lines: any[] }) {
+    return this.budgetPlanning.updateLines(dto.planId, dto.lines);
+  }
+
+  @Put('budget-plans/:year/inflation')
+  updateBudgetPlanInflation(@Param('year') year: string, @Body() dto: { inflationRate: number }) {
+    return this.budgetPlanning.updateInflation(parseInt(year, 10), dto.inflationRate);
+  }
+
+  @Put('budget-plans/:year/status')
+  advanceBudgetPlanStatus(@Param('year') year: string, @Body() dto: { status: string }, @Req() req: any) {
+    return this.budgetPlanning.advanceStatus(parseInt(year, 10), dto.status, req.user.sub);
+  }
+
+  @Delete('budget-plans/:year')
+  deleteBudgetPlan(@Param('year') year: string) {
+    return this.budgetPlanning.deletePlan(parseInt(year, 10));
+  }
 }