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/tests/test_formula.py

@@ -10,7 +10,7 @@ from pathlib import Path
 
 import pytest
 
-from nsp.evidence.formula_store import ConceptFormula, retrieve_formula, save_formula
+from tht.evidence.formula_store import ConceptFormula, retrieve_formula, save_formula
 
 
 def test_formula_retrieval_by_concept(tmp_path):
@@ -72,7 +72,7 @@ def test_retrieve_empty_on_missing_dir(tmp_path):
 
 def test_concept_formula_decision_types_exist():
     import typing
-    from nsp.decisions import DecisionType
+    from tht.decisions import DecisionType
     args = typing.get_args(DecisionType)
     assert "concept_formula_approved" in args
     assert "concept_formula_rejected" in args