Sopana v1.5.0

Sopāna v1.5.0 — Real character sprites in Cinematic + per-theme music

Every character now looks like itself (Cinematic)

• Generated a backlit sprite for each character (pilgrim, sage, devotee, wanderer; founder,
  engineer, designer, investor; lion, monkey, turtle, crow, deer; runner, reader, sprout, star).
• In the Cinematic view each player is rendered as their chosen character — no longer one plain
  tinted world image — each on the dark backlit stage with a soft player-colour glow.

Theme-appropriate music (no more constant buzz)

• Founder's Climb, Panchatantra Trail and Habit Heroes now play their own generated looping music
  (bright synth / warm folk / playful chiptune) instead of the constant drone.
• Snake & Ladders — Original keeps its temple drone, as intended.
• Mute still controls everything.

Generators added (tooling/gen_char_sprites.py, gen_theme_music.py). 19/19 tests pass.