Add target comparison modal, integration goal progress, and session planning + full catalog expansion

Features added this session:
- Target comparison: side-by-side overlay (CompareModal) from Targets page via ⊕ button on each row; shows altitude curves, key times, filter recommendations and per-filter integration progress for two targets simultaneously
- Integration goal progress dashboard card: per-target keeper minutes vs goal hours (from CLAUDE.md §16.3) broken down by filter, with color-coded progress bars; powered by new stats.integration_goals backend query
- Session planning timeline: Gantt-style "Plan Tonight" section on Dashboard (PlanningTimeline component) — search targets, set durations, sequential scheduling from dusk, overrun warnings, clipboard export
- Slew-optimized run order toggle (nearest-neighbor sort by RA/Dec angular distance)
- Best Nights 14-day card + Monthly Highlights card on Dashboard

Catalog expansions:
- Sharpless (Sh2), VdB, LDN, Barnard dark nebulae, LBN, Melotte, Collinder, Gum, RCW, Abell PN, Abell GC, PGC bright subset
- Caldwell/Arp/Melotte/Collinder number columns + cross-reference maps
- Weather score multiplier applied to composite sort
- galaxy_cluster type (ACO badge) throughout TypeBadge, CSS, filter chips

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/styles/global.css

@@ -97,6 +97,9 @@ input:focus, select:focus, textarea:focus {
 .type-badge.reflection_nebula { background: var(--type-reflection); color: #fff; }
 .type-badge.dark_nebula { background: var(--type-dark); color: var(--text-mid); }
 .type-badge.nebula     { background: var(--teal); color: #fff; }
+.type-badge.galaxy_cluster { background: #7b3f9e; color: #fff; }
+.type-badge.galaxy_group { background: #4a5268; color: #fff; }
+.type-badge.interacting_galaxy { background: #5c4070; color: #fff; }
 
 /* Quality chips */
 .quality-chip {