Add Artemis compudynamics implementation plan; add stress campaign fixture

The 30-replicate Artemis surface-stress campaign ran across all three
architectures: 30 reps x 50 trials x 3 arches = 4500 trials, zero failures.
The block_words.c stale-pointer cache-aliasing fix holds at scale.

Adds ART-STRESS-CAMPAIGN (block 4174) plus ART-STRESS-REP rep-tagging in
the CSV header/summary emitters, so a multi-replicate run is distinguishable
in the serial log. Campaign auto-invoke is left enabled in block 4170 for
now; Makefile.starkernel's QEMU boot deadlines stay at 12h to accommodate
long-running experiments.

Adds docs/working/architecture/ARTEMIS-COMPUDYNAMICS-IMPLEMENTATION-PLAN-20260802.md,
which documents the real gap this campaign exposed: block heat and message
heat do not decay at all. ART-TICK has zero call sites anywhere in the tree,
and HERMES-TICK has zero C call sites -- every caller is Hera poking it by
hand. BLK-HEAT@/MSG-HEAT@ read a number nothing ages, so blocks never reap
by cooling and message TTL never expires on its own.

The plan mirrors word-level physics as the reference model: lazy decay at
each access point against vm->heartbeat.tick_count, plus a bounded
background sweep with a resumable cursor (the existing answer to "sweeping
22,998 blocks per tick is too expensive"). Phase 1 Artemis, Phase 2 Hermes,
Phase 3 K participation deferred behind the Logical BAM.

The plan's preamble also records a wrong turn taken while investigating:
chasing VM-fleet heat instead of block heat, and building synthetic
Hera-driven VM-EXEC calls to force a physics reading -- which TRIPOD.md
prohibits outright. That work was reverted; the record is kept so it isn't
repeated.

Status: plan approved in shape, NOT final and NOT started. Six open
questions need answers and further design discussion is pending.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

This commit is contained in: