Teach release planner to update generated Node loader diagnostics

The v0.26.1 release planner updated the generated Node loader version comparisons but left the diagnostic literals at `expected 0.26.0` in the Discovery, Evidence, Relay, and BReg loaders.

The release PR corrected the generated output directly. Update the planner rewrite for `generated-binding-loader` files and add a focused regression assertion that the enforced version and reported expected version stay aligned.

This is follow-up tooling hardening and is not a v0.26.1 release blocker.

Inizia con la riscrittura del release planner per i file generated-binding-loader e verifica come aggiorna i confronti tra versioni e i literal diagnostici. Aggiungi un’asserzione di regressione mirata che copra i loader Discovery, Evidence, Relay e BReg e verifica che la versione imposta e la versione attesa riportata rimangano allineate.

Scritto dal modello di indicizzazione a partire dal testo della issue.