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>

docs/language/ease/_section.md

@@ -0,0 +1,7 @@
+---
+id: ease
+title: Ease
+order: 6
+---
+
+Tween curves — the "juice" layer. Each takes a normalized amount <code>t</code> in <code>0.0</code>..<code>1.0</code> and returns an eased <code>fixed</code>, ready to feed to <code>Math.lerp</code>. All deterministic fixed-point.

docs/language/ease/ease-back.md

@@ -0,0 +1,22 @@
+---
+id: ease-back
+name: Ease.back
+category: ease
+kind: namespace-method
+tokens: Ease.back
+sig: Ease.back(t) -> fixed
+tip: Ease in with a small backward anticipation.
+order: 3
+ns: Ease
+member: back
+---
+
+Returns an ease-in that first dips slightly below <code>0</code> before shooting forward — the anticipation windup that gives a motion snap. Because it undershoots, the eased value can go negative near the start, so use it where a little overshoot reads as lively rather than wrong.
+
+```ludic
+program Demo {
+  handler Step phase Update {
+    let s = Math.lerp(rest, poke, Ease.back(progress))
+  }
+}
+```

docs/language/ease/ease-bounce.md

@@ -0,0 +1,22 @@
+---
+id: ease-bounce
+name: Ease.bounce
+category: ease
+kind: namespace-method
+tokens: Ease.bounce
+sig: Ease.bounce(t) -> fixed
+tip: Ease out with a settling bounce.
+order: 4
+ns: Ease
+member: bounce
+---
+
+Returns an ease-out that overshoots and bounces a few times before settling at <code>1.0</code>, like a ball dropping to the floor. Great for coins landing, badges popping, or a menu that lands with character.
+
+```ludic
+program Demo {
+  handler Step phase Update {
+    let y = Math.lerp(top, floor_y, Ease.bounce(progress))
+  }
+}
+```

docs/language/ease/ease-in.md

@@ -0,0 +1,22 @@
+---
+id: ease-in
+name: Ease.in
+category: ease
+kind: namespace-method
+tokens: Ease.in
+sig: Ease.in(t) -> fixed
+tip: Accelerate from rest (quadratic ease-in).
+order: 0
+ns: Ease
+member: in
+---
+
+Returns <code>t * t</code> — motion that starts slow and speeds up. Feed the result to <code>Math.lerp</code> as the blend amount so a value accelerates into its target. The input <code>t</code> is expected in <code>0.0</code>..<code>1.0</code>.
+
+```ludic
+program Demo {
+  handler Step phase Update {
+    let x = Math.lerp(start_x, end_x, Ease.in(progress))
+  }
+}
+```

docs/language/ease/ease-in_out.md

@@ -0,0 +1,22 @@
+---
+id: ease-in_out
+name: Ease.in_out
+category: ease
+kind: namespace-method
+tokens: Ease.in_out
+sig: Ease.in_out(t) -> fixed
+tip: Ease in and then out (smoothstep).
+order: 2
+ns: Ease
+member: in_out
+---
+
+Returns the smooth <code>3t^2 - 2t^3</code> S-curve: slow at both ends, fastest in the middle. Use it for a polished there-and-back or point-to-point move that neither jerks off the mark nor slams into the target.
+
+```ludic
+program Demo {
+  handler Step phase Update {
+    let a = Math.lerp(0.0, 1.0, Ease.in_out(progress))
+  }
+}
+```

docs/language/ease/ease-out.md

@@ -0,0 +1,22 @@
+---
+id: ease-out
+name: Ease.out
+category: ease
+kind: namespace-method
+tokens: Ease.out
+sig: Ease.out(t) -> fixed
+tip: Decelerate to rest (quadratic ease-out).
+order: 1
+ns: Ease
+member: out
+---
+
+Returns <code>t * (2 - t)</code> — motion that starts fast and slows as it arrives. The most natural-feeling easing for things settling into place, like a panel sliding in or a camera coming to rest.
+
+```ludic
+program Demo {
+  handler Step phase Update {
+    let y = Math.lerp(top, rest_y, Ease.out(progress))
+  }
+}
+```