feat(design): foundation pass — dusty violet palette, warm parchment light, Inter + JetBrains Mono

Applies the FabledSword + Scribe iteration palette to theme.css end to
end: indigo (#7c3aed) → dusty violet (#5B4A8A) accent, cool grey →
Obsidian/Iron/Pewter dark surfaces, warm parchment (#F5F1E8) light
mode, Inter body + JetBrains Mono code loaded alongside Fraunces, and
neutral hairline scrollbars (chrome is structural, not branded).

Adds the action token set (--color-action-primary Moss,
--color-action-secondary Bronze, --color-action-destructive Oxblood,
--color-action-ghost-border Pewter) but does not yet reclassify any
buttons — surface-phase work. Buttons remain dusty-violet gradients in
the meantime, by design.

Removes deprecated --color-accent-warm; replaces concrete usages with
--color-text-secondary (dates, flavor copy) or --color-warning (paused
status). Sweeps hardcoded indigo literals in component scoped CSS so
they don't bypass the token system.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/views/HomeView.vue

@@ -569,7 +569,7 @@ function formatUpcomingTime(event: EventEntry): string {
   border-radius: var(--radius-lg);
   padding: 1.25rem 1.5rem;
   margin-bottom: 1.75rem;
-  box-shadow: 0 2px 16px rgba(124, 58, 237, 0.08), 0 1px 4px rgba(0, 0, 0, 0.06);
+  box-shadow: 0 2px 16px rgba(91, 74, 138, 0.08), 0 1px 4px rgba(0, 0, 0, 0.06);
 }
 .hero-top {
   display: flex;
@@ -612,13 +612,13 @@ function formatUpcomingTime(event: EventEntry): string {
   font-size: 0.9rem;
   font-weight: 600;
   white-space: nowrap;
-  box-shadow: 0 1px 6px rgba(124, 58, 237, 0.3);
+  box-shadow: 0 1px 6px rgba(91, 74, 138, 0.3);
   transition: opacity 0.15s, box-shadow 0.15s;
   flex-shrink: 0;
 }
 .btn-workspace-hero:hover {
   opacity: 0.9;
-  box-shadow: 0 3px 14px rgba(124, 58, 237, 0.45);
+  box-shadow: 0 3px 14px rgba(91, 74, 138, 0.45);
 }
 
 .hero-milestones { margin-bottom: 0.75rem; }
@@ -760,8 +760,8 @@ function formatUpcomingTime(event: EventEntry): string {
   font-weight: 500;
 }
 .urgency-in-progress {
-  background: color-mix(in srgb, #7c3aed 15%, transparent);
-  color: #7c3aed;
+  background: color-mix(in srgb, #5B4A8A 15%, transparent);
+  color: #5B4A8A;
 }
 .urgency-todo {
   background: color-mix(in srgb, var(--color-text-muted) 12%, transparent);