[Feature] Active story badges + active-first sorting on Trending/MCap

[realproject7]

Overview

Make active stories (still accepting new plots) visually distinct and prioritized in relevant sort modes.

1. Active badge on book card

Add an "Active" badge on the book-shaped story card, positioned above the plot count badge at the bottom.

┌─────────────┐
│ MYSTERY     │  ← genre badge (existing)
│             │
│  Story      │
│  Title      │
│             │
│ Active      │  ← new badge, same style as genre
│ 3 plots     │  ← existing plot count
└─────────────┘

Badge design:

• Same style as the genre/category badge (small rounded pill, point color text)
• Text: "Active" for active stories, "Completed" or "Expired" for sunset/expired
• Color: accent/brown for Active, muted/grey for Completed

Book outline:

• Active stories: thicker border with accent color (e.g., border-2 border-accent)
• Completed stories: normal thin border (existing style)

Active = sunset === false AND (has_deadline === false OR deadline not expired)

2. Active-first sorting (Trending/MCap only)

Active stories sort above completed stories, but only for these sort modes:

• Trending — active stories first, then completed
• Market Cap ([Feature] Add Market Cap sort option to story discovery #957) — active stories first, then completed

These sorts should NOT apply active-first:

• Recent — pure chronological, active status irrelevant
• TVL — value-based, expired stories with high TVL deserve their rank

Implementation: for Trending/MCap sorts, use a two-level sort:

ORDER BY 
  (CASE WHEN sunset = false AND (has_deadline = false OR deadline_not_expired) THEN 0 ELSE 1 END),
  mcap DESC  -- or trending metric

3. Completed/Expired visual dimming

Completed stories on the discover page:

• Book card has slightly reduced opacity or greyed-out tone
• "Completed" badge in muted color (replaces "Active" position)
• No accent border (normal thin border)

Files

• Story card component (book shape) — add Active/Completed badge + border styling
• Discover page — add active-first logic for Trending/MCap sorts
• API route for discovery — support active-first ordering

Acceptance Criteria

• "Active" badge on book card (same style as genre badge)
• "Completed"/"Expired" badge for sunset/expired stories
• Active stories have thicker accent-colored border
• Trending/MCap sorts: active stories first, then completed
• Recent/TVL sorts: unaffected by active status
• Completed stories visually dimmed