feat(resume): Resume in the kebab menu (A1) + harden the resume kickoff (A2)

A1 — SessionMenu gains a Resume item, gated to status!=="finalized" && !archived
(matching the backend's 409 read-only guard), wired in AppShell to doResume ->
POST /sessions/:id/resume. SessionMenu.test.tsx (3 tests); frontend 96/96, tsc clean.

A2 — diagnosis-first clean-room repro driving `pi --mode rpc` with the backend's
exact resume handshake shows the cold-start stall NO LONGER reproduces on pi
0.79.4 (8/8 chained into `tht session show` + `read SKILL.md` in-turn, fresh and
partway sessions). The earlier narrate-and-stop predates the pi upgrade.
Defense-in-depth anyway: RIPRENDI_KICKOFF hardened to force the in-turn tool call
(gate_resume_kickoff.test.js + live regression 2/2). Gate JS 34/34.

PROJECT_STATE open-item #1 (resume stall) flipped to RESOLVED; cross-model resume
robustness folded into workstream G.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

harness/.pi/extensions/tht-gate.js

@@ -104,6 +104,9 @@ const RIPRENDI_KICKOFF =
 	"comando di shell ne' `/skill:...`).\n" +
 	"3. Determina l'ultima fase completata dai fatti persistiti (le decisioni sono la verita': " +
 	"cio' che non e' registrato non e' avvenuto) e riprendi da li'.\n" +
+	"Esegui i passi 1-2 ORA, in QUESTO stesso turno, chiamando subito i tool (`bash` per " +
+	"`tht session show`, `read` per la skill): NON limitarti a dichiarare l'intenzione e NON " +
+	"terminare il turno prima di aver chiamato i tool.\n" +
 	"Valgono le stesse regole non negoziabili: una domanda per volta, conferma esplicita, tool " +
 	"reviewer_*, niente phase advance/reopen o decision add da shell, una fase alla volta.";