Stage H: DoE rebuilt on BIRTH/SEND/KILL, defs-only workloads; work heat floor on contact (FABRIC-3.8 §3.9, §3.13.7)

Workload capsules the DoE births are definitions only; each defines WL-RUN
(its old birth-time work plus its entry word twice) and WL-DONE-ARGS. The
driver births N workers, SENDs each 'WL-RUN WL-DONE-ARGS SEND', waits in an
ordinary loop for N MU-DONE messages, KILLs them (parked idle), and emits
the marker. The serialized VM-EXEC round-robin is gone.

Kernel: no switch checkpoint after a payload's last word; work heat is the
assessed per-beat charge, and a VM gaining work is raised to the busy set's
floor (Captain Bob's ruling) -- fixes a live stall where a busy-waiting Hera
never yielded, without serializing batch starts.

Evidence: cfg-4 rows spread evenly over Hera and all 8 worker slots (44k
switches); full cfg-4 trials on amd64/aarch64/riscv64 end fail=0 with 8/8
KILL dead; Stage G interleave byte-identical on all three. Acceptance:
dict_hash unchanged, relay 3, idle growth 0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

capsules/workload-4.4th

@@ -30,5 +30,6 @@ Block 2132
     DO-PI
   LOOP
 ;
-RUN-PI
-." 4:dopi-ok" CR
+( FABRIC-3.8 3.9: defs only; the DoE SENDs WL-RUN )
+: WL-RUN RUN-PI ." 4:dopi-ok" CR RUN-PI RUN-PI ;
+: WL-DONE-ARGS S" MU-DONE" S" Hera" ;