fix(ui): restructure projections tab & fix growth projection bugs

[halfguru]

This PR introduces a restructured, chronological dashboard layout for the Projections tab and fixes several bugs:

1. Chronological Dashboard Layout:

   • Grouped the pre-retirement accumulation charts into a single section with a segmented tab switcher: [ Standard Growth ] [ Contribution vs. Growth ] [ Market Volatility ]. This collapses the vertical page length by 50% on both mobile and desktop.
   • Placed the post-retirement Retirement Drawdown chart below in its own dedicated section.
   • Utilizes Tailwind responsive breakpoints to reflow headers side-by-side on desktop while stacking neatly on mobile.

2. Growth Chart Toggles (Conservative/Realistic/Optimistic):

   • Added segmented yield toggles directly inside the GrowthChart card representing Conservative (-2%), Realistic (baseline), and Optimistic (+2%) return scenarios.
   • Fixed styling to ensure buttons display with correct dark-theme backgrounds (fixing the white-button issue).

3. Contributions vs Growth Negative Value Bug:

   • Fixed a dollar-basis mismatch where nominal contribution additions were subtracted from inflation-deflated real balances, resulting in negative growth calculations.
   • Contributions are now deflated dynamically using the inflation rate in real dollar mode, and growth is clamped to $\ge 0$.