feat(stdlib): finish Crypto (CSPRNG + base64) and add Uuid.* library (#19 #16)

Crypto (#19): add the OS cryptographically-secure random surface
(random_bytes/random_hex/random_u32, reading /dev/urandom) and a standard
base64 encoder, completing the library alongside the existing SHA-256/
HMAC-SHA256/verify_hmac/hex/ct_equal. All pure integer IR, C-free.

Uuid (#16): a new namespace for stable, collision-free IDs — v4 (random) and
v7 (time-ordered) generation, plus parse/is_valid/to_text/equals/nil. UUIDs are
canonical lowercase 36-char strings; v4 and v7's random tail draw from the
crypto CSPRNG, so both carry the documented determinism caveat (mint at the
edges, never inside lockstep simulation). Reuses the crypto prelude's
fn_secure_bytes / fn_hex_encode.

- examples/library/{crypto,uuid}.ludic: known-answer vectors (SHA-256, HMAC,
  base64 per RFC 4231/4648) and structural invariants (uuid version/variant
  bits, parse/equals), wired into `x test` (now 51 passed).
- docs: per-symbol pages for every new method + a new Uuid section; inventory
  and impl-vs-docs coverage check pass.
- seed regenerated; `x bootstrap-cfree` fixpoint holds.

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

tools/docgen/inventory.json

@@ -404,6 +404,21 @@
     "crypto-hmac_sha256",
     "crypto-verify_hmac",
     "crypto-hex",
-    "crypto-ct_equal"
+    "crypto-ct_equal",
+    "crypto-random_bytes",
+    "crypto-random_hex",
+    "crypto-random_u32",
+    "crypto-base64"
+  ],
+  "uuid": [
+    "uuid-new",
+    "uuid-v4",
+    "uuid-new_v7",
+    "uuid-v7",
+    "uuid-parse",
+    "uuid-is_valid",
+    "uuid-to_text",
+    "uuid-equals",
+    "uuid-nil"
   ]
 }

tools/x/selfhost.ludic

@@ -29,6 +29,7 @@ function selfhost_frags() -> []pointer {
   push(f, "selfhost/emit_text.ludic")
   push(f, "selfhost/emit_hash.ludic")
   push(f, "selfhost/emit_crypto.ludic")
+  push(f, "selfhost/emit_uuid.ludic")
   push(f, "selfhost/emit_list.ludic")
   push(f, "selfhost/emit_ease.ludic")
   push(f, "selfhost/emit_collide.ludic")

tools/x/test.ludic

@@ -97,6 +97,11 @@ function cmd_test() -> int {
   feat_case("lang/detach", "", "15 1 25 0", "detach.ludic (attach/detach + @OnAttach/@OnDetach)")
   feat_case("lang/reason", "", "503 1009", "reason.ludic (@OnDespawn reason: Despawned vs Quit)")
 
+  # standard-library namespaces, each a self-contained `entry` program asserted
+  # against known-answer vectors (crypto) or structural invariants (uuid/noise).
+  feat_case("library/crypto", "", "1 2 3 4 5 6 7 8 9", "crypto.ludic (Crypto SHA-256/HMAC/base64 KAT + CSPRNG shape)")
+  feat_case("library/uuid", "", "1 2 3 4 5 6 7 8 9 10", "uuid.ludic (Uuid v4/v7 format, version/variant, parse/equals)")
+
   # issue #9: the Time/Date/Duration/Clock stdlib, driven from its own `entry`.
   net_case("lang/offline_rewards", "13 650 2026-08-30 0")