Layer 2: multi-axis archetype classifier; the FLEX fallback is gone

A player is a blend across independent axes, not one label. Skubal is a STARTER
and a strikeout arm and a ground-ball arm and a control arm — four true things
at once, and single-label classification threw three of them away.

AXIS INDEPENDENCE WAS MEASURED, NOT ASSUMED. Correlations over the live store
(467 batters, 531 pitchers); anything |r| >= 0.70 is one underlying trait and
was collapsed so we never show one trait as two archetypes. Batter k% ~ whiff%
+0.89, hard-hit% ~ exit velo +0.88, chase% ~ swing% +0.87, chase% ~ bb% -0.72;
pitcher k% ~ whiff% +0.76, gb% ~ fb% -0.73 — all collapsed.

The survivors are genuinely orthogonal, and one result is worth stating: pitcher
velocity correlates +0.14 with K%, +0.07 with whiff% and +0.07 with GB%.
Velocity is NOT a proxy for missing bats — a hard thrower who misses no bats is
a real distinct type, so CANNON earns its own axis rather than being folded into
STRIKEOUT. Pitcher K% ~ GB% is -0.10, so PUNCHOUT and SINKER are independent,
which is exactly the multi-axis thesis.

Cut-lines are the measured p75 (distinctive) and p90 (elite), per role where the
tails differ even when the medians agree: reliever GB% p90 is 54.1 against a
starter's 48.9, both with a median of 42.5.

THE FALLBACK IS DELETED. classify() used to return FLEX (mlb) / SHIELD (wnba) /
CONNECTOR (nba) at weight 1.0 when nothing scored — "could not classify"
rendered as a fully-confident classification of a real archetype, with
descriptive education copy attached. 8 of 18 MLB players carried it, and FLEX
could never be earned because its only scoring input had zero writers. Every
sport now does what MMA already did: unclassified is absent.

Induced on real players. Skubal: STARTER, throws L, WHIFF + SEAM + PINPOINT, all
elite. Judge: BOMBER + GRINDER + WHIFF RISK — elite power, patient, strikes out,
three true things. Kwan: SURGEON + SNIPER + SLASH with NO power claimed (0.4
barrel% is absent, not "low power"). Josh Bell, who used to classify as DRIVER:
empty blend, "No standout profile — league-average across every measured axis."
Alan Roden, who was FLEX at weight 1.0 on 21 PA: every axis absent, "Not enough
plate appearances yet — no profile claimed."

Per-axis honest-absence holds: a velo-less pitcher keeps every other axis, and
NO DATA is distinguishable from LEAGUE-AVERAGE rather than collapsing into one
shrug. The full vector is stored for Layer 3; only the top three distinctive
traits surface.

Three existing tests asserted the fallback and were updated to assert absence.
One of them surfaced a real robustness gap: classify(sport, null) threw, because
an explicit null does not trigger a default parameter and every scorer
dereferences its argument. Guarded.

Every baseball name is accounted for in docs/ARCHETYPE-AXES.md — built, alias,
tier, or shelved with its unlock condition. Zero orphans; cross-sport names left
for their sport.

Tests 3601 passed / 293 suites.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCNgGSt5qvcLxaeQqa7Zpj

tests/unit/archetypeService.test.js

@@ -116,10 +116,19 @@ describe('archetypeService — WNBA classification', () => {
   });
 });
 
-describe('archetypeService — graceful fallback', () => {
-  it('returns a fallback archetype for empty stats (never crashes)', () => {
-    expect(svc.classifyNBA({}).primary).toBeTruthy();
-    expect(svc.classifyMLB({}).primary).toBeTruthy();
-    expect(svc.classify('badsport', {}).primary).toBeNull();
+describe('archetypeService — HONEST ABSENCE on empty stats (Session 69)', () => {
+  it('returns NO archetype for empty stats — never a fallback bucket', () => {
+    // Was: a fallback archetype at weight 1.0 (FLEX/SHIELD/CONNECTOR), i.e.
+    // "could not classify" rendered as a confident classification with
+    // descriptive education copy. 8 of 18 MLB players carried it.
+    for (const s of [svc.classifyNBA({}), svc.classifyMLB({}), svc.classify('badsport', {})]) {
+      expect(s.primary).toBeNull();
+      expect(s.blend).toEqual([]);
+    }
+  });
+
+  it('still never crashes on junk input', () => {
+    expect(() => svc.classify('mlb', null)).not.toThrow();
+    expect(() => svc.classify(null, {})).not.toThrow();
   });
 });