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/.pi/extensions/gate/builders.js

@@ -3,7 +3,7 @@
 // Each function turns plain params into a ui_request descriptor object. No Pi
 // context, no I/O -- this is the part of the gate that is fully testable in L1
 // (in JS, in-language, no Python mirror). The glue (emission via ctx.sendRaw,
-// anti-bypass, the no-limbo loop) is in nsp-gate.js and is verified at L2.
+// anti-bypass, the no-limbo loop) is in tht-gate.js and is verified at L2.
 //
 // The 6 widget kinds: info, select, multiselect, freetext, artifact-gate, artifact.
 // `widget` is an open field (a new kind needs a renderer, not infra changes);