feat(types): Dict + Set string-keyed containers (#54)

Types phase 4 — containers. A splice-on-demand open-addressing hash table
(runtime/native/dict.ludic, FNV-1a, linear probing, tombstones, grow at 0.7)
behind two namespaces:

- Dict.* — string -> int map: new/set/get/get_or/has/remove/size/clear/keys.
  Resource counts, id/name registries. O(1) average vs a linear list scan.
- Set.* — set of strings: new/add/has/remove/size/clear/members. Tags,
  unlocked achievements, visited tiles. Shares the same table.

Values are int (also an entity handle / small id); Value.* covers richer
maps. [T; N] inline fixed arrays remain future work — typed buffers and []T
slices already cover heap-backed arrays.

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

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

selfhost/backend/emit_call.ludic

@@ -365,6 +365,30 @@ function emit_ns_call(ns: pointer, meth: pointer, e: Node) -> Val {
     if (meth == "rescale") { bare = "decimal_rescale";  push(labels, "d"); push(labels, "places") }
     if (meth == "str")     { bare = "decimal_str";      push(labels, "d") }
   }
+  # Dict.* / Set.* -> the hash-table engine (runtime/native/dict.ludic, spliced
+  # on demand). Ordinary Ludic functions, so the generic call path resolves them
+  # to @fn_dict_* / @fn_set_* and keeps their return types (Dict / int / bool /
+  # []pointer).
+  if (ns == "Dict") {
+    if (meth == "new")     { bare = "dict_new" }
+    if (meth == "set")     { bare = "dict_set";    push(labels, "d"); push(labels, "key"); push(labels, "value") }
+    if (meth == "get")     { bare = "dict_get";    push(labels, "d"); push(labels, "key") }
+    if (meth == "get_or")  { bare = "dict_get_or"; push(labels, "d"); push(labels, "key"); push(labels, "fallback") }
+    if (meth == "has")     { bare = "dict_has";    push(labels, "d"); push(labels, "key") }
+    if (meth == "remove")  { bare = "dict_remove"; push(labels, "d"); push(labels, "key") }
+    if (meth == "size")    { bare = "dict_size";   push(labels, "d") }
+    if (meth == "clear")   { bare = "dict_clear";  push(labels, "d") }
+    if (meth == "keys")    { bare = "dict_keys";   push(labels, "d") }
+  }
+  if (ns == "Set") {
+    if (meth == "new")     { bare = "set_new" }
+    if (meth == "add")     { bare = "set_add";     push(labels, "s"); push(labels, "key") }
+    if (meth == "has")     { bare = "set_has";     push(labels, "s"); push(labels, "key") }
+    if (meth == "remove")  { bare = "set_remove";  push(labels, "s"); push(labels, "key") }
+    if (meth == "size")    { bare = "set_size";    push(labels, "s") }
+    if (meth == "clear")   { bare = "set_clear";   push(labels, "s") }
+    if (meth == "members") { bare = "set_members"; push(labels, "s") }
+  }
   if (ns == "Grid") {
     if (meth == "line")          { bare = "grid_line";          push(labels, "x0"); push(labels, "y0"); push(labels, "x1"); push(labels, "y1") }
     if (meth == "blocked")       { bare = "grid_blocked";       push(labels, "x"); push(labels, "y"); push(labels, "wall") }

selfhost/frontend/parse.ludic

@@ -176,6 +176,7 @@ function p_postfix() -> Node {
     if is_op(".") { pi = pi + 1; let m = node(E_MEMBER); m.a = e; m.s = eat_id(); e = m
       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 == "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
@@ -423,6 +424,7 @@ var loaded_paths: []pointer
 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_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
@@ -608,6 +610,13 @@ function maybe_splice_runtime() -> void {
     do_import("runtime/native/bignum.ludic")
     cur_dir = saved
   }
+  # any program that uses Dict.*/Set.* gets the hash-table engine spliced in
+  # (self-contained — only compiler intrinsics — so a plain tool works too).
+  if g_uses_dict {
+    cur_dir = ""
+    do_import("runtime/native/dict.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).
@@ -723,6 +732,7 @@ function parse_program() -> void {
   g_toggled_layers = new []pointer
   g_uses_regex = false
   g_uses_bignum = false
+  g_uses_dict = false
   g_uses_query = false
   g_uses_reflect = false
   g_uses_esys = false