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/pages/board-planning/components/AssessmentChangeForm.tsx

@@ -117,32 +117,27 @@ export function AssessmentChangeForm({ opened, onClose, onSubmit, initialData, l
 
         {isSpecial && (
           <>
-            <Group grow>
-              <NumberInput
-                label="Total Amount"
-                value={form.specialTotal}
-                onChange={(v) => setForm({ ...form, specialTotal: Number(v) || 0 })}
-                min={0}
-                decimalScale={2}
-                thousandSeparator=","
-                prefix="$"
-              />
-              <NumberInput
-                label="Per Unit Amount"
-                value={form.specialPerUnit}
-                onChange={(v) => setForm({ ...form, specialPerUnit: Number(v) || 0 })}
-                min={0}
-                decimalScale={2}
-                prefix="$"
-              />
-            </Group>
             <NumberInput
-              label="Installments"
-              description="1 = one-time lump sum, 6 = spread over 6 months, etc."
-              value={form.specialInstallments}
+              label="Per Unit Amount"
+              description="Total amount each unit will be assessed"
+              value={form.specialPerUnit}
+              onChange={(v) => setForm({ ...form, specialPerUnit: Number(v) || 0 })}
+              min={0}
+              decimalScale={2}
+              thousandSeparator=","
+              prefix="$"
+            />
+            <Select
+              label="Duration"
+              description="How the assessment is collected"
+              value={String(form.specialInstallments)}
               onChange={(v) => setForm({ ...form, specialInstallments: Number(v) || 1 })}
-              min={1}
-              max={60}
+              data={[
+                { value: '1', label: 'One-time (lump sum)' },
+                { value: '3', label: 'Quarterly (3 monthly payments)' },
+                { value: '6', label: '6 months' },
+                { value: '12', label: 'Annual (12 monthly payments)' },
+              ]}
             />
           </>
         )}