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>

docs/language/angle/angle-add.md

@@ -0,0 +1,22 @@
+---
+id: angle-add
+name: Angle.add
+category: angle
+kind: namespace-method
+tokens: Angle.add
+sig: Angle.add(a, b) -> fixed
+tip: Add two angles (wrapped).
+order: 5
+ns: Angle
+member: add
+---
+
+Adds two angles and wraps the result back into range.
+
+```ludic
+program Demo {
+  handler Step phase Update {
+    facing = Angle.add(facing, turnRate)
+  }
+}
+```