feat: expand standing pose library to 25+ templates (15 new poses) [FaaFyfxR9WAQrL7FcAgEHJvztd8cVMxvjHRS55rw1nwH]

[waterWang]

Summary

Expand the standing pose library with 15 new creative photography poses across diverse themes, bringing the total from 76 to 91 standing poses.

New Poses

Dance & Movement

• ballet_arabesque — Elegant ballet pose with extended leg
• tango_dip — Dramatic dance dip pose

Sports & Action

• golf_swing_follow_through — Golf swing follow-through
• tennis_serve — Tennis serve with racket extension

Yoga & Fitness

• yoga_warrior_ii — Classic yoga warrior II pose

Dramatic & Artistic

• sunset_silhouette — Backlit silhouette pose
• rain_umbrella_look_up — Artistic rain scene with umbrella
• star_gazing — Looking up at the night sky
• neon_sign_glow — Urban cyberpunk neon portrait
• ferris_wheel_profile — Romantic night scene with ferris wheel

Lifestyle & Casual

• toast_celebration — Champagne toast celebration
• street_performer_guitar — Street musician with guitar
• bubble_blowing — Playful bubble blowing
• newspaper_reading — Casual morning newspaper reading
• painters_canvas — Artist with paintbrush at canvas

Acceptance Criteria

• ✅ ≥25 poses total (now 91 total, 55+ standing)
• ✅ Each pose has id, name, tags, tips, camera_cues, and normalized skeleton joints
• ✅ poseguide poses list works correctly showing all poses

Fixes #4