feat(stdlib): namespaced standard library (issue #2)

Implement the bulk of the namespaced-stdlib proposal (workshopsoft/ludic#2):
156 namespace methods across Math, Text, List, Ease, Collide, World, Net,
Sys, Save, Mem, extended Screen, Color functions, extended Random, and Time.
All deterministic fixed-point; self-hosting (C-free bootstrap fixpoint holds).

Compiler (selfhost/):
- Math.*: sqrt/sin/cos/tan/atan2/asin/acos (fixed-point runtime prelude —
  bit-by-bit isqrt, 256-entry interpolated sine table, Ross atan2), plus
  hypot/dist/dist2/deg_to_rad/rad_to_deg/posmod/wrap/ping_pong/snapped/
  move_toward/smoothstep/lerp/remap/sign/floor/ceil/round.
- Text.* (complete): upper/lower/trim/repeat/pad, split/join/replace,
  and the libc-backed queries.
- List.* (complete): insert/remove_at/remove/sort plus the earlier ops.
- Ease.* (in/out/in_out/back/bounce) and Collide.* (rects/point_rect/
  circles/rect_circle).
- Phase 3: World/Net/Sys/Save namespaced over the bare builtins (byte-
  identical IR) and Mem.* (bytes/words/copy/fill/peek/poke).
- Screen.* extended (line/circle/fill_circle/triangle/fill_triangle via new
  runtime primitives; sprite/sprite_scaled aliases), Color.* functions,
  Random.* (value/int/sign), Time.* (frame/delta/elapsed/now — new
  game-loop frame counter).
- Fix a lexer bug: fixed-point literals with >4 fractional digits overflowed.

Docs & tooling:
- 129 new per-symbol doc pages; gen.py made data-driven (namespaces
  discovered from the docs, no hardcoded list); new check-impl.py enforces
  that every implemented namespace method / keyword / type / phase has a
  doc page, wired into `x test-tools`. Document the previously-undocumented
  keywords (break/continue/where/entry/new/public + and/or/not tokens).
- LSP: namespaced signature help (ns_method_sig) covering every namespace.

Tests: 12 new self-host/regression tests + a golden render for the drawing
primitives. All suites green (selfhost 21, regression 45, tools 29).

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

SCENES-DESIGN.md

@@ -3,7 +3,7 @@
 > **Status: S0 shipped; S1–S6 are design.** The base construct — `scene` /
 > `layer` / `on enter` / `on exit` / `become`, lowered to the implicit machine of
 > §3 and §9 — is implemented and tested ([`examples/scenes.ludic`](examples/scenes.ludic),
-> a `test.sh` check). The extensions in §4–§8 (scene-owned entities, richer
+> a `bin/x test` check). The extensions in §4–§8 (scene-owned entities, richer
 > layers, the overlay stack, scene-local state, transition parameters) are still
 > design targets. This document reaches deliberately past the thin sketch so we
 > can decide the shape before building each one. §11 lists the open decisions.
@@ -310,7 +310,7 @@ Each is independently shippable and testable, matching how the repo phases work.
   exit`/`become` lowered to the implicit `machine`; the active scene is
   snapshotted per phase so exactly one scene's layers dispatch in any phase.
   [`examples/scenes.ludic`](examples/scenes.ludic) compiles, runs, and is checked
-  by `test.sh`. This is the floor everything else builds on.
+  by `bin/x test`. This is the floor everything else builds on.
 - **S1 — `@OnEnter`/`@OnExit` annotation form** (E5, cheap once S0 exists).
 - **S2 — layer toggle & pause** (E2) on top of the existing `enable`/`disable`.
   ✅ *Toggle shipped* (via EVENTS-DESIGN EV1 layers): `enable layer L` / `disable