fix: assessment scenarios UX tweaks and projection improvements

- Reorder sidebar: Assessment Scenarios now directly under Budget Planning
- Simplify special assessment form: remove Total Amount, keep Per Unit only
- Replace Duration field from free-text installments to dropdown (one-time/quarterly/6mo/annual)
- Update Change column display to show total per-unit with duration label
- Fix Reserve Coverage to use planned capital project costs instead of budget expenses
- Include capital_projects table in projection engine alongside projects table
- Replace actions dropdown menu with inline Edit/Remove icon buttons
- Remove Refresh Projection button (projection auto-refreshes on changes)

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

frontend/src/components/layout/Sidebar.tsx

@@ -67,8 +67,8 @@ const navSections = [
     label: 'Board Planning',
     items: [
       { label: 'Budget Planning', icon: IconReportAnalytics, path: '/board-planning/budgets' },
-      { label: 'Investment Scenarios', icon: IconScale, path: '/board-planning/investments' },
       { label: 'Assessment Scenarios', icon: IconCalculator, path: '/board-planning/assessments' },
+      { label: 'Investment Scenarios', icon: IconScale, path: '/board-planning/investments' },
       { label: 'Compare Scenarios', icon: IconGitCompare, path: '/board-planning/compare' },
     ],
   },