feat(types): Huge + Angle + Percent polish numeric types (#55)

Types phase 5 (polish). A splice-on-demand numeric runtime
(runtime/native/numeric.ludic, built on the inline Math.* trig) behind three
namespaces:

- Huge.* — idle big numbers (normalized mantissa x 10^exponent): from/add/
  sub/mul/neg/cmp/sign/mantissa/exp/str (scientific 1.23e45). Display-scale,
  not lockstep-exact (BigInt/Decimal for exactness).
- Angle.* — auto-wrapping radians: from_degrees/to_degrees/wrap/sin/cos/add/
  diff (shortest signed rotation)/lerp (shortest arc).
- Percent.* — clamped [0,1]: clamp/of/lerp/apply.

Remaining phase-5 items are already covered (duration=Duration.*,
rune=Unicode.*, i64=long) or need a type-checking pass (handle, typed name,
other sized ints) — tracked for later.

Wired: parser splice trigger (g_uses_numeric), emit_call dispatch, reseeded
seed, a self-asserting example (examples/library/numeric.ludic + feat_case),
per-symbol docs + inventory. All suites green incl. golden renders byte-
identical and the bootstrap fixpoint.

NOTE: fixed `const`s lower to raw-int-typed values (emit_call N_CONST), which
breaks fixed comparisons — the runtime uses inline fixed literals instead.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

selfhost/frontend/parse.ludic

@@ -177,6 +177,7 @@ function p_postfix() -> Node {
       if e.a.kind == E_ID and e.a.s == "Regex" { g_uses_regex = true }   # splice the regex runtime on demand
       if e.a.kind == E_ID and (e.a.s == "BigInt" or e.a.s == "Decimal") { g_uses_bignum = true }   # splice the bignum runtime on demand
       if e.a.kind == E_ID and (e.a.s == "Dict" or e.a.s == "Set") { g_uses_dict = true }   # splice the hash-table runtime on demand
+      if e.a.kind == E_ID and (e.a.s == "Huge" or e.a.s == "Angle" or e.a.s == "Percent") { g_uses_numeric = true }   # splice the huge/angle/percent runtime on demand
       if e.a.kind == E_ID and e.a.s == "Query" { g_uses_query = true }   # splice the ECS spatial-query runtime on demand
       if e.a.kind == E_ID and e.a.s == "Reflect" { g_uses_reflect = true }   # force-emit the reflection ABI (Reflect.* reads the world schema)
       if e.a.kind == E_ID and e.a.s == "Light" { g_uses_light = true }   # splice the 2D light-accumulation pass on demand
@@ -425,6 +426,7 @@ var cur_dir: pointer
 var g_uses_regex: bool = false    # a program mentioned Regex.* -> splice the regex runtime
 var g_uses_bignum: bool = false   # a program mentioned BigInt.*/Decimal.* -> splice the bignum runtime
 var g_uses_dict: bool = false     # a program mentioned Dict.*/Set.* -> splice the hash-table runtime
+var g_uses_numeric: bool = false  # a program mentioned Huge.*/Angle.*/Percent.* -> splice the numeric runtime
 var g_uses_query: bool = false    # a program mentioned Query.* -> splice the query runtime + reflection ABI
 var g_uses_reflect: bool = false  # a program mentioned Reflect.* -> force-emit the reflection ABI
 var g_uses_light: bool = false    # a program mentioned Light.* -> splice the 2D light pass
@@ -617,6 +619,13 @@ function maybe_splice_runtime() -> void {
     do_import("runtime/native/dict.ludic")
     cur_dir = saved
   }
+  # any program that uses Huge.*/Angle.*/Percent.* gets the numeric runtime
+  # spliced in (it builds on Math.*, which lowers inline, so a plain tool works).
+  if g_uses_numeric {
+    cur_dir = ""
+    do_import("runtime/native/numeric.ludic")
+    cur_dir = saved
+  }
   # any program that uses Query.* gets the ECS spatial-query helpers spliced in;
   # they read entity state through the reflection ABI (emit_decl force-emits it
   # for a Query program even when it declares no events).
@@ -733,6 +742,7 @@ function parse_program() -> void {
   g_uses_regex = false
   g_uses_bignum = false
   g_uses_dict = false
+  g_uses_numeric = false
   g_uses_query = false
   g_uses_reflect = false
   g_uses_esys = false