fix: complete Spanish-to-English translation for RoadmapTab

Added missing translation keys for visible UI elements:
- Investment Scenarios section (title, subtitle, tooltip)
- Table headers (Scenario, Investment, Recurring, Savings, Margin, Payback, ROI, Risk)
- Risk labels (Low, Medium, High)
- Wave card labels (Savings/year, Margin/year, Savings:)
- Timeline badges (Conditional, risk indicators)
- Tooltips (enabler wave, negative margin, projected ROI, adjusted ROI)

Build verified successfully

https://claude.ai/code/session_03272424-c661-4002-a75e-2f81579fdd6e

frontend/locales/en.json

@@ -686,9 +686,13 @@
       "legendRisk": "= Risk"
     },
     "comparison": {
+      "title": "Investment Scenarios",
+      "subtitle": "Comparison of options by commitment level",
+      "tooltip": "ROI based on industry benchmarks. Adjusted ROI considers implementation risk factors.",
       "investment": "Investment",
       "recurring": "Recurring",
       "savings": "Savings",
+      "adjusted": "adjusted",
       "margin": "Margin",
       "payback": "Payback",
       "roi3y": "3y ROI",
@@ -697,7 +701,18 @@
       "recommendation": "Recommendation",
       "recommendationEnabler": "Recommendation (Enabler)",
       "enabler": "Enabler",
-      "recommended": "Recommended"
+      "recommended": "Recommended",
+      "savingsPerYear": "Savings/year",
+      "marginPerYear": "Margin/year",
+      "savingsLabel": "Savings:",
+      "conditional": "Conditional",
+      "riskLow": "Low",
+      "riskMedium": "Medium",
+      "riskHigh": "High",
+      "enablerWaveTooltip": "Enabler wave - its value is in unlocking subsequent waves",
+      "negativeMarginTooltip": "Negative annual margin",
+      "projectedRoiTooltip": "Projected ROI. Validate with pilot.",
+      "adjustedRoiTooltip": "ROI adjusted for implementation risk"
     },
     "entryCriteria": {
       "wave1TierFrom": "HUMAN-ONLY (4), AUGMENT (3)",