feat(dashboard): trim methodology first sentence further

The 'Hours here are estimated' phrasing was redundant with the 'estimated'
pill on the Hours KPI tile — the pill is the visual signal, the methodology
doesn't need to repeat it. Left is just 'Git records what changed and when,
but not how long it took.' which sets up the next paragraph.

src/components/dashboard/methodology.tsx

@@ -17,9 +17,7 @@ export function Methodology({ metrics }: { metrics: ProjectMetrics }) {
 
       <div className="space-y-2.5 text-sm text-text-secondary">
         <p>
-          Git records what changed and when, but not how long it took. Hours
-          here are <strong className="text-text-primary">estimated</strong> from
-          the timing of commits, not measured.
+          Git records what changed and when, but not how long it took.
         </p>
 
         <p>