Write the room's re-simulation plausibility rule as a pure function in packages/ — the remainder of #465 criterion 3

[mgcronin]

What this carries

The remainder of #465's third acceptance
criterion, which #486 takes #465 to merge without
meeting:

The re-simulation rule written as a pure function in packages/ with a mutation-tested rejection
case (physically impossible power for the declared mass).

ADR 0028 D-2
§"What a room checks" specifies the rule's shape — four numbered rules and a physics version on
the wire — and deliberately does not implement it. The reason is #465's own standard applied to
itself, and it is recorded in that ADR rather than only here: validation code for a room that does
not exist, over a transport that does not exist, with thresholds nobody has agreed, reads to a
reviewer as evidence that the validation question was settled. CLAUDE.md §4a's "a documented
command nobody has run is the most expensive kind of wrong", in a new place.

This issue is filed so that the remainder lives in the tracker rather than only in an ADR's prose and
a merged pull request's body — CLAUDE.md §7's named repair for a closing keyword that went further
than intended.

Blocked on

Block	What clears it
There is no room (owner decision D6)	#7
The W/kg ceilings are nobody's decision yet	ADR 0028 Q3. The rule's shape is settled; its numbers are not, and ADR 0006 R1 means the answer has to say where they came from rather than take somebody's table
ADR 0028 D-0's third block	Spike 0005 §5 Question A — counsel on US 9,174,085 claim 1

Acceptance criteria

• The rule is a pure function in packages/, implementing ADR 0028 D-2 rules 1–4: report
  admissibility; a power–duration ceiling judged over a window rather than per sample; a breach
  that flags rather than ejects; and the client/room disagreement published as a signal.
• A mutation-tested rejection case — an implausible sustained power for the declared mass —
  with the mutation and what went red in the pull request body (CLAUDE.md §5).
• An admissible-but-extreme case that is not rejected, so the rule is not a function that
  rejects everything. A single 1800 W sample is a sprint; an 1800 W five-minute mean is not a
  person (ADR 0028 D-2 rule 2).
• An inadmissible report coasts the rider at zero power and is never extrapolated (rule 1),
  asserted rather than described.
• Q3's ceilings are answered with their provenance recorded, or the function takes them as a
  parameter and the caller supplies them — whichever the answer to Q3 makes true.

Two things the same work should pick up, both from #486's review

1. The coefficient set ADR 0028 D-1 names lives under apps/, where a room cannot read it.
   RIDING_POSITIONS and GAME_ROLLING_RESISTANCE_COEFFICIENT are in apps/web/src/game/rider.ts,
   and eslint.config.js's boundaries/dependencies block forbids packages/ importing apps/
   (CLAUDE.md §4d). Move them into packages/ and have the game read them from there — one set
   rather than two that can drift. D-1 says so and points here.
2. A second vector in packages/physics/src/agreement.test.ts at the race's own configuration.
   Today that file pins the package's defaults, which are the base every race configuration is built
   on but not the configuration a race runs (D-1's table). A vector at the race's actual drag area
   and C_RR was deliberately not added in Offline correctness and racing groundwork: the stale rung numbering (#485), the tab left behind by another tab's update (#483), the live-racing patent read (#466) and the race-fairness ADR (#465) #486: the numbers live across a boundary that package
   may not import, so a copied literal would pin a configuration this package cannot see move —
   silently stale, which is the defect shape this repository keeps closing. Once (1) is done the
   vector costs five lines and has a constant to point at.

What this is NOT

• Not a room, a transport or a client. ADR 0028 D-0 holds: nothing races until [EPIC] Instance Sync API and Activity Ingestion #7, counsel and
  the owner's five questions clear.
• Not #69. This rule produces a flag; Implement leaderboard integrity: implausible-effort exclusion and flagging #69
  owns what is done about implausible efforts.

Refs #465 · Refs #486 · Refs #16 · Refs #7 · Refs #69