feat(init): built-in diff viewer and auto-commit with --yes

Inizia da formatResult() e buildSummaryLines() in src/lib/init/formatters.ts, quindi segui WizardOptions.yes e ApplyPatchsetPayload in src/lib/init/types.ts attraverso src/lib/init/wizard-runner.ts. Verifica come il wizard visualizza attualmente i riepiloghi e gestisce --yes. Il lavoro è completato quando i file sottoposti a patch mostrano diff unificati colorati, --yes esegue il commit successivamente e la modalità interattiva mantiene la richiesta di revisione.

Summary

After the init wizard applies file changes, the CLI prints a static message — "Please review the changes above before committing." — but doesn't actually show the diffs. Users have to manually inspect the working tree to understand what changed. Additionally, when running with --yes (non-interactive mode), the wizard still stops without committing, requiring manual intervention.

This issue proposes two improvements:

1. Built-in diff viewer — display inline diffs of all applied patches so users can review changes without leaving the terminal
2. Auto-commit with --yes — when the user opts into non-interactive mode, automatically commit the wizard's changes after displaying the diff summary

Current Behavior

• formatResult() in src/lib/init/formatters.ts builds a summary of changed files (create/modify/delete) via buildSummaryLines() and displays it with note()
• A static log.info("Please review the changes above before committing.") message follows
• The --yes flag auto-selects prompts and confirms but does not commit the resulting changes
• Full patch data (including diffs) is available in ApplyPatchsetPayload but is not surfaced to the user

Proposed Behavior

• After the wizard completes, render a colored unified diff of each patched file (using the patch data already available in ApplyPatchsetPayload)
• When --yes is set, auto-commit the changes after displaying the diff summary (skip the "please review" message)
• When --yes is not set, show the diff and keep the existing review prompt

References

• src/lib/init/formatters.ts — formatResult() and buildSummaryLines()
• src/lib/init/types.ts — WizardOptions.yes and ApplyPatchsetPayload
• src/lib/init/wizard-runner.ts — wizard execution flow

Originated from a review comment by @BYK.