feat(compiler): self-hosting spec + generator multi-enum support

- Add speckl-compile.speckdl — compiler formally specified in SpeckDL
- Generator: multi-enum detection, value→enum mapping, trailing comma cleanup
- Emit blocks collapsed to single-line (parser limitation)
- Generated artifacts: provenance, BOMs, WAT, TypeScript (2 known bugs → engineering#8)

compiler/test-output/RetryHandler.specbom.spdx.json

@@ -13,7 +13,7 @@
     "spdxVersion": "3.0.1",
     "dataLicense": "CC0-1.0",
     "creationInfo": {
-      "created": "2026-05-03T18:51:34.105Z",
+      "created": "2026-05-03T20:13:42.868Z",
       "createdBy": [
         "Organization: Speckl",
         "tool: speckl-compile-0.2.0"
@@ -27,7 +27,7 @@
           "@type": "spdx:Tool",
           "name": "speckl-compile"
         },
-        "timestamp": "2026-05-03T18:51:34.105Z",
+        "timestamp": "2026-05-03T20:13:42.868Z",
         "comment": "Review type: manual"
       }
     ]