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>

tools/docgen/inventory.json

@@ -412,6 +412,26 @@
     "decimal-rescale",
     "decimal-str"
   ],
+  "dict": [
+    "dict-new",
+    "dict-set",
+    "dict-get",
+    "dict-get_or",
+    "dict-has",
+    "dict-remove",
+    "dict-size",
+    "dict-clear",
+    "dict-keys"
+  ],
+  "set": [
+    "set-new",
+    "set-add",
+    "set-has",
+    "set-remove",
+    "set-size",
+    "set-clear",
+    "set-members"
+  ],
   "duration": [
     "duration-seconds",
     "duration-minutes",