v1.3.0

Flux Hourglass 1.3.0

A focused upgrade to the visual core of the timer — the sand pile now
behaves like sand instead of plateauing two-thirds of the way, the
display reacts to physical gravity, and a brand-new LED grid mode
sits alongside the original hourglass.

Highlights

• Pile fills the full screen. Previously the heap topped out at
  roughly two thirds of the height regardless of duration. The pile
  now tracks elapsed time 1:1, so when the timer ends the screen is
  fully covered. A baseline catch-up keeps the pile honest even on
  long durations where per-grain deposition would otherwise lag.
• Softer, finer texture. Grains shrank from 3.0 dp to 1.4 dp and
  the column count nearly doubled (50 → 90), giving the pile a much
  smoother silhouette and a more powdery surface.
• Real gyro response. The accelerometer is no longer cosmetic. The
  falling stream bends with the gravity vector, and the heap on the
  floor immediately slumps toward the lower side when you tilt the
  device — strong tilts trigger an extra pour pass for a more decisive
  reaction.
• New LED mode. A "전광판" alternative renders the screen as a
  16 × 32 grid of LED-style cells that light up bottom-to-top in
  proportion to elapsed time. When every cell is lit, time is up.
  Toggle between S A N D and L E D from a new tab row at the top
  of the setup screen; the choice is persisted alongside the last
  duration.
• Bolder typography. Secondary labels were close to invisible at
  the old 0.25–0.4 alpha range. They have been lifted to 0.55–0.8 and
  bumped from Thin / ExtraLight to Light (with Medium on the
  selected mode tab), so the chrome reads clearly without losing the
  minimalist character.

Implementation notes

• ParticleSystem now owns a baseline lift step that adds the deficit
  between the target average height (1 - remainingFraction) * h and
  the current average back into every column. The lift is capped at
  h * 0.004 per frame so it never produces a visible jolt.
• pvx is no longer reset to zero each frame; particles integrate
  horizontal gravity and despawn when they leave the canvas. Spawn
  positions get mild jitter plus a small directional bias so the
  stream visibly leans when the device is tilted.
• Slumping uses an asymmetric threshold (1.0 ± biasX) with four
  passes per frame, escalating to six passes when |gravityX| > 2.0.
• LED mode reuses the same touch-reveal + pause/reset overlay as the
  sand mode through a shared RunningOverlay composable; the renderer
  itself is a single Canvas that lights cells in row-major order
  from the bottom.
• TimerPreferences gained a mode field backed by a string
  preference (SAND / LED), defaulting to SAND for first runs and
  upgrading users.