test: port the .wwi observers to ww; retire 989_m2wwi + 989_wwileaf

test/byteid/wwi_test.ww carries every assertion of both carriers: the
M2 producer gate (ascii/strings/getopt driver-combined positives with
byte-id + wwdump -a re-parse, the synth decl-kind/type-node sweep with
the #47 @symbol round-trip, the #48 types export-def gate, and the
negative private-nominal leak with both-stage identical reject
diagnostics), plus the #11 wwileaf decl-less-leaf rows (package-line
leaf, cross-stage .wwi byte-id, importer resolution + .s byte-id).
Byteid carriers 10 -> 8; docs counts move; the byteid ww target gains
the wwdump prereq its re-parse legs invoke.

docs/test-system-v2.md

@@ -36,10 +36,12 @@ The live declarative compiler corpus has 1,495 fixtures and 2,990 C/WW cells:
 338 expected rejections (314 shared and 24 stage-specific), 17 compile-only
 successes, 198 exit-zero programs, and 942 explicit-exit programs.
 
-133 native C carriers remain. They are partitioned exactly once as five
-in-process units, 10 byte/artifact gates, six bootstrap gates, one platform
+131 native C carriers remain. They are partitioned exactly once as five
+in-process units, 8 byte/artifact gates, six bootstrap gates, one platform
 gate, and 111 residual compiler, package-layout, ABI, diagnostic-observer,
-driver, linker, or FFI gates. Rows migrated to fixtures or native `@test`
+driver, linker, or FFI gates. The `.wwi` round-trip observers are
+ww-native (`test/byteid/wwi_test.ww`, replacing `989_m2wwi_run` and
+`989_wwileaf_run`). Rows migrated to fixtures or native `@test`
 owners were removed from those carriers; there is no compatibility execution
 path for retired rows. 74 former byte/artifact carriers whose only assertion
 was a cstage-vs-wwstage `.s` byte-compare of sources now living in the