feat(ludic.weather): spells of weather as a mechanic package

The kinds and their odds are data the game hands in; a port asks whether this
machine owns the world, the hour, the night, the odds from a kind, what the
story wants of the sky (a front, a hold, a clear night), the front's kind and
length, and a seed. Its own dice; a new spell, a clearing, lightning and a
wanted front are facts on weather_facts(); its own save section.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.weather/verbs.ludic

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+# verbs.ludic - the only way the sky changes from outside: a morning, a reset, the host's word
+# a new trip: clear sky, a still-ish wind, nothing forecast; the dice from the world's seed
+export function weather_reset() -> void {
+  var seed = 1
+  if wx_world != null and wx_world.seed != null { seed = wx_world.seed() }
+  wx_dice = rng_new(seed)
+  let clear = wx_clear_kind()
+  wx_state = clear
+  wx_next = clear
+  wx_forecast = clear
+  wx_left = 30.0
+  wx_amount = 0.0
+  wx_forced = false
+  wx_wind = 0.2
+  wx_dir = 0.0
+  wx_ground = 0.0
+  wx_flash = 0.0
+  wx_thunder_t = 0.0
+  wx_clear_t = 0.0
+  wx_wet_today = false
+  wx_wet_yesterday = false
+  q_clear(weather_facts())
+}
+
+# a new day's forecast: seven times in ten it is the next spell. A front already on its way
+# stays on its way.
+export function weather_morning() -> void {
+  if weather_kind_count() == 0 { return }
+  wx_wet_yesterday = wx_wet_today or wx_kinds[wx_state].wet
+  wx_wet_today = false
+  if wx_forced {
+    wx_forecast = wx_next
+    return
+  }
+  wx_forecast = wx_pick_next(wx_state)
+  if rng_float(wx_dice) < 0.7 { wx_next = wx_forecast }
+}
+
+# the sky outright: a spell of `kind` now, `left` hours of it, at full strength when not clear
+# (staging, a test, a story beat)
+export function weather_set(kind: int, next: int, left: float) -> void {
+  wx_state = kind
+  wx_next = next
+  wx_left = left
+  wx_amount = 1.0
+  if wx_kinds[kind].clear { wx_amount = 0.0 }
+}
+
+# what the machine that owns the world says the sky is; a new spell is a fact here too
+export function weather_told(kind: int, next: int, left: float, amount: float, wind: float, dir: float, forecast: int) -> void {
+  let was = wx_state
+  wx_state = kind
+  wx_next = next
+  wx_left = left
+  wx_amount = amount
+  wx_wind = wind
+  wx_dir = dir
+  wx_forecast = forecast
+  if kind != was { wx_fact(WEATHER_BEGAN, kind, was) }
+}
+
+export function weather_set_wind(strength: float, dir: float) -> void {
+  wx_wind = strength
+  wx_dir = dir
+}
+
+export function weather_set_ground(wet: float) -> void { wx_ground = wet }
+export function weather_set_flash(f: float) -> void { wx_flash = f }