refactor(harness): renaming prodotto tht (Onda -1)

Thoth (tht) è il prodotto, PSD è il cliente. Nessun riferimento al contesto
clinico nel codice.

Rinomine:
- comando+package nsp→tht (dir nsp/→tht/, 46 import, pyproject entry point)
- gate nsp-gate.js→tht-gate.js (+ rewrite token, relayIfNspFails→relayIfThtFails)
- workspace chirone.{example,test}.yaml→tht.{example,test}.yaml (generici)
- env THOTH_→THT_ (19 var) + NSP_ stragglers (NSP_HARNESS_ROOT, NSP_SESSION)
- commenti/docstring chirone/psdwp3/policlinico neutralizzati ('the reference
  implementation', 'the DWH')

Aggiunto [tool.setuptools.packages.find] include=['tht*'] (necessario: l'auto-
discovery rompeva con tht/ + workspaces/ come top-level multipli).

.env operatore aggiornato in-place (prefissi THT_, valori preservati, gitignored).

Verifica: pytest 109 passed, npm test 14 pass, tht phase meta --json OK, zero
residui nsp/THOTH_/NSP_/chirone nel package.

harness/tht/mschema/eligibility.py

@@ -0,0 +1,93 @@
+"""Classificazione di column eligibility (principio trasversale Thoth).
+
+Vedi docs/superpowers/specs/2026-06-13-tht-column-eligibility-principle.md.
+Il testo ampio (lettere di dimissione, note, anamnesi) è ignorato ovunque; i dati
+provengono solo da numerici, enum, temporali, booleani e testo breve.
+"""
+
+import re
+
+from tht.config import EligibilityConfig
+from tht.db.sampling import is_text_type
+from tht.mschema.models import ColumnAnnotation, ColumnPhysical, PhysicalSchema
+
+_NUMERIC_PREFIXES = (
+    "smallint", "integer", "bigint", "numeric", "decimal", "real", "double", "money",
+)
+_TEMPORAL_PREFIXES = ("date", "time", "timestamp", "interval")
+_LEN_RE = re.compile(r"\((\d+)\)")
+
+
+def _declared_len(pg_type: str) -> int | None:
+    m = _LEN_RE.search(pg_type)
+    return int(m.group(1)) if m else None
+
+
+def classify_column(
+    pg_type: str,
+    is_enum: bool,
+    sampled_avg: float | None,
+    sampled_max: int | None,
+    cfg: EligibilityConfig,
+) -> tuple[bool, str]:
+    """Classifica una colonna come (eligible, reason). Funzione pura, senza I/O."""
+    t = pg_type.strip().lower()
+    if t.endswith("[]"):
+        return False, "wide_text"
+    if is_enum:
+        return True, "enum"
+    if t.startswith(_NUMERIC_PREFIXES):
+        return True, "numeric"
+    if t.startswith("boolean"):
+        return True, "boolean"
+    if t.startswith(_TEMPORAL_PREFIXES):
+        return True, "temporal"
+    if t.startswith("uuid"):
+        return True, "code"
+    if is_text_type(t):
+        declared = _declared_len(t)
+        if declared is not None and declared <= cfg.max_declared_len:
+            return True, "short_text"
+        # bound grande o text/varchar non vincolato: decide il dato campionato
+        if sampled_avg is None or sampled_max is None:
+            return False, "wide_text"
+        if sampled_avg <= cfg.max_avg_length and sampled_max <= cfg.max_sampled_len:
+            return True, "short_text"
+        return False, "wide_text"
+    return False, "wide_text"
+
+
+def _sampled_stats(examples: list[str]) -> tuple[float | None, int | None]:
+    if not examples:
+        return None, None
+    lengths = [len(v) for v in examples]
+    return sum(lengths) / len(lengths), max(lengths)
+
+
+def classify_all(physical: PhysicalSchema, cfg: EligibilityConfig) -> None:
+    """Assegna eligible/eligibility_reason a ogni colonna (in-place) e azzera gli
+    examples delle colonne ignored. Da chiamare DOPO add_examples."""
+    ignore_by_name = {name.lower() for name in cfg.ignore_columns}
+    for table in physical.tables.values():
+        for column_name, column in table.columns.items():
+            if column_name.lower() in ignore_by_name:
+                # colonna di servizio (ETL/audit): ignorata a prescindere dal tipo
+                column.eligible = False
+                column.eligibility_reason = "ignored_by_name"
+                column.examples = []
+                continue
+            avg, mx = _sampled_stats(column.examples)
+            eligible, reason = classify_column(column.type, column.is_enum, avg, mx, cfg)
+            column.eligible = eligible
+            column.eligibility_reason = reason
+            if not eligible:
+                column.examples = []
+
+
+def effective_eligibility(
+    column: ColumnPhysical, annotation: ColumnAnnotation | None
+) -> tuple[bool, str]:
+    """Eligibilità effettiva: l'override in annotations.yaml vince sul fisico."""
+    if annotation is not None and annotation.eligible is not None:
+        return annotation.eligible, "override"
+    return column.eligible, column.eligibility_reason