FABRIC.md: resolve four of five §17.7 questions -- Stadium heat already conserved

The Stadium cell's heat field (stadium.h:64, item 3.1) was already declared
Q48.16 conserved share of 1.0, citing §19.1, before this section was reopened.
L0 already has a real conservation mechanism (items 3.4/3.5 consume it); it
has just never been fed. execution_heat and Stadium heat are two different
fields with two different jobs -- item 4.1 feeds the second, not converts the
first. Resolves the promotion-threshold, dict_hash-baseline, parity, and
new-loop questions on that basis; states an explicit one-governor-per-build
rule mirroring §17.3. The per-dispatch transfer rule and its cost remain
open and still block item 4.1.

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

FABRIC.md

@@ -1078,66 +1078,88 @@ that matters. The total stays fixed; only the partition shifts.
 Decide how big the Stadium is at runtime. Do not decide what an entry is, or how entries
 are addressed, at runtime.
 
-### 17.7 Word-level heat conservation — LEANING, paper only, blocks item 4.1
+### 17.7 Word-level heat conservation — LEANING, one question open, blocks item 4.1
 
-Item 4.1 (hot words onto the Stadium, §25.5) needs `DictEntry.execution_heat` converted into
-the Stadium's Q48.16 `heat` field. The obvious move — `q48_from_u64(execution_heat)`, a pure
-representation change, no semantics touched — was proposed and **rejected 2026-08-04**:
-Captain Bob wants real conservation for word heat too, on the same footing as §19.1's
-fleet-level invariant, not just a unit conversion.
+Item 4.1 (hot words onto the Stadium, §25.5) needs word patrons to carry a Stadium `heat`
+share. The obvious move — `q48_from_u64(execution_heat)`, a pure representation change
+grafted onto `DictEntry.execution_heat`, no real conservation — was proposed and **rejected
+2026-08-04**: Captain Bob wants real conservation for word heat, on the same footing as
+§19.1's fleet-level invariant, not just a unit conversion of the existing counter.
 
-This is open. It is *not* a smaller version of §19.1 — it conflicts with two things already
-load-bearing, and both have to be resolved on paper before any code touches Loop #1:
+**Corrected premise (2026-08-05): this was never a choice between converting
+`execution_heat` or leaving it alone.** `include/starkernel/vm/stadium.h:64` already declares
+the Stadium cell's `heat` field as `Q48.16, conserved share of 1.0 (§19.1)` — written when
+item 3.1 was done, before this section was reopened. Items 3.4 (density = heat ÷ mass) and
+3.5 (admit if denser than the least-dense resident) already consume it as a real, relative,
+conserved quantity. **L0 already has a genuine conservation mechanism; it has just never
+been fed, because nothing has been admitted to the Stadium yet.** `execution_heat` and
+Stadium `heat` are two different fields with two different jobs. Item 4.1's task is to feed
+the second one from word dispatch, not to convert the first one into it. That reframing
+resolves four of the five questions this section left open:
 
-1. **The promotion threshold breaks.** `hotwords_cache_lookup()` promotes a word on
-   `execution_heat > HOTWORDS_EXECUTION_HEAT_THRESHOLD` (`50`, absolute, against an unbounded
-   counter — `physics_hotwords_cache.h:87`). A conserved share of `Q48_ONE` (65536) split
-   across however many words are resident cannot be compared against `50` in any consistent
-   way. §17.3, decided the same day this question was raised, says plainly "execution heat
-   (Loop #1) is what promotes a word" — treating the existing counter, and its absolute
-   threshold, as the mechanism. Conservation needs a *relative* trigger instead (density-rank
-   within the resident set, margin above the resident median, something else) — a real
-   change to Loop #1's promotion rule, not a units change.
-2. **`dict_hash` moves.** `capsule_dict_hash_hook()` hashes exactly two things per entry:
-   name and `execution_heat`. That hash is the parity baseline every item this phase has been
-   verified against. If `execution_heat`'s value now comes from a transfer instead of an
-   increment, it changes on every dispatch for a different reason than before, and the
-   baseline moves in the same commit that introduces the change. The design has to say
-   explicitly what happens to parity comparisons made before vs. after — not leave it
-   implicit.
+1. ~~**The promotion threshold breaks.**~~ **RESOLVED — it doesn't, because nothing replaces
+   it.** `HOTWORDS_EXECUTION_HEAT_THRESHOLD` belongs to the old cache mechanism, and §17.3's
+   resolution already retires that mechanism's *effect* under `__STARKERNEL__` regardless of
+   this question. Item 4.1 admits by item 3.5's rule instead — density relative to the
+   least-dense resident — which is already the relative trigger this bullet said conservation
+   would require, and it is already built.
+2. ~~**`dict_hash` moves.**~~ **RESOLVED — it doesn't move, because `execution_heat` is not
+   touched.** `capsule_dict_hash_hook()` keeps hashing name and `execution_heat` exactly as
+   today; the counter keeps incrementing and decaying exactly as today. Stadium `heat` is not
+   part of `dict_hash` and item 4.1 does not need to add it there. No baseline discontinuity,
+   no "before vs. after" comparison problem — there is nothing to reconcile.
+3. **What transfers, from whom, on every dispatch — and its cost.** **Still open.** This is
+   real work, not dissolved by the reframing above: on a kernel-build word dispatch, some
+   Q48.16 amount has to move toward the touched word's cell from the rest of the VM's
+   resident pool — the same shape as `vm_physics_transfer()`'s clamped subtract/add at the
+   fleet level, or the proportional redistribution at `capsule_vm_physics.c:334`, but nobody
+   has picked the exact rule or measured its cost on this path yet. This sits in both the
+   hosted and kernel dispatch primitive today (`physics_execution_heat_increment()`), but
+   under the resolution below the *new* transfer is kernel-only, alongside — not replacing —
+   that existing increment. Still blocks item 4.1's code.
+4. ~~**What happens to `dict_hash` and parity comparisons that predate this change.**~~
+   **RESOLVED by #2 above** — nothing predates a change that isn't being made to the hashed
+   field.
+5. ~~**A new "L9" loop, or composes into an existing one.**~~ **RESOLVED — composes into L0.**
+   The Stadium engine (§18) already owns a conserved heat wire per cell; item 4.1 populates
+   that existing wire for the word patron kind. It is not a new loop and needs no name.
 
-There's a third thing underneath both: real conservation means the *increment itself* becomes
-a *transfer* — heat pulled toward the touched word from the rest of the resident set, or from
-the full dictionary, on every single word dispatch. That is the hottest path in the entire VM,
-in both hosted and kernel builds, and Loop #1 is one of the seven feedback loops this project
-has a formal-verification claim about (0.000% CV across 90 runs). This does not get touched
-speculatively.
+**What sums to what, and admission semantics — settled by code already written, not
+re-derived here:** per-VM Stadium, summing to 1.0 across every patron resident in that VM's
+quota (words, blocks, ACLs, messages together, not a word-only sub-pool) — matching §21.4's
+"K conserved here, independently" and the `stadium.h:64` field comment. No reset on
+admit/evict: the sum stays invariant across *any* call per §19.1's own conservation check, so
+admission is itself a transfer, not a reset — mirroring `capsule_vm_physics.c`'s VM-birth
+pattern, where a new patron starts at 0 (or a starter share) and is topped up by transfer,
+never by manufactured heat.
 
-**Captain Bob's own first sketch (2026-08-04, to be developed further, not yet a ruling):** a
-quantity between 0 and 1, possibly derived from something that already exists as a DoE output
-parameter, kept conserved by its own dedicated loop rather than folded into an existing one —
-explicitly *not* gated by L8 the way L1–L7 are (§18.1's "L8 cannot be gated... L0 cannot be
-gated" bookend structure is the closest existing precedent for an always-on, ungated loop).
-`stale_word_ratio` (`doe_metrics.c:273`, `stale_word_count / word_count`, already bounded
-[0,1], already flowing into the DoE CSV) is one candidate for "something that already exists"
-worth checking against when this gets picked back up — not proposed as the answer, just the
-nearest existing fit to "0 to 1, already measured."
+**One governor per build — states explicitly what closes the §11/§25.5 "never two live heat
+mechanisms" gap:**
 
-**Open, to settle before item 4.1 writes any Loop #1 code:**
+- **Kernel builds:** `execution_heat` stops being a *decision input* once item 4.1 lands — it
+  keeps incrementing, decaying, and getting hashed exactly as today (ENTROPY@, ACL words,
+  diagnostics, `dict_hash` all keep working unchanged), but it no longer governs residency.
+  Stadium `heat`/density governs Stadium residency instead.
+- **Hosted builds: unchanged**, per §17.3's own resolution — no Stadium exists there,
+  `execution_heat` keeps governing the old cache exactly as it does today.
 
-- What sums to what: per-VM over its resident set? Over the full dictionary? Does the sum
-  reset on residency change (admit/evict), or is that a different mechanism wearing
-  conservation's name?
-- What replaces the absolute promotion threshold, given a relative/conserved quantity can't
-  be compared against a fixed constant the way `execution_heat > 50` is today.
-- What transfers, from whom, on every dispatch — and its cost, given this sits on the hottest
-  path in the VM, before it is approved for the dispatch loop in either build.
-- What happens to `dict_hash` and to parity comparisons that predate this change.
-- Whether this is really a new, ungated loop (a candidate "L9," by the naming scheme in
-  §18.1) or something that composes into an existing one — not decided here.
+This is the same per-build split §17.3 already ruled for the cache itself; word-level heat
+conservation follows it rather than inventing a second shape.
 
-**Nothing in this section authorizes touching `execution_heat`'s current increment
-behaviour, Loop #1, or `dict_hash` before this section reads DECIDED.**
+**Open, to settle before item 4.1 writes any transfer code:**
+
+- The exact per-dispatch transfer rule (pull from a proportional share of current residents?
+  from a designated "unclaimed" pool representing non-resident dictionary words? something
+  else) and its measured cost on the dispatch path, kernel build only.
+- Whether `rolling_window_seed_hotwords_cache()`'s POST warm-start
+  (`rolling_window_of_truth.c:786`) needs a Stadium-side counterpart to seed word patrons'
+  initial `heat` distribution — noted here as the natural seeding site, not designed.
+
+**Nothing in this section authorizes touching the per-dispatch transfer rule, or wiring
+`stadium_admit`/`stadium_dispatch` for words, before the open bullet above reads DECIDED.
+`execution_heat`'s current increment/decay behaviour and `dict_hash` are explicitly out of
+scope for item 4.1 — this section's earlier ban on touching them no longer applies, because
+nothing here proposes touching them.**
 
 ---