fix: explain completed issue reopen behavior

[krasnoperov]

Summary

• post a clear Linear comment when PatchRelay restores reopened completed work to Done
• point follow-up work to a new Linear issue and link the merged delivery PR when available
• keep the state repair best-effort when the Linear comment API fails

Verification

• node --experimental-transform-types --test test/merged-linear-completion-reconciler.test.ts (10/10)
• pnpm typecheck
• pnpm lint
• pnpm test (1025/1025)

[review-quill]

Verdict: 🛑 Request changes — The explanation must be posted only after the state restoration succeeds to avoid misleading duplicate comments during retryable Linear failures.

[review-quill]

🚨 If Linear creates the comment but transiently rejects setIssueState, each normal retry creates another comment and claims a restoration that has not happened.

Suggested change

	await this.commentOnCompletedIssueReopen(issue, linear);
	const updated = await linear.setIssueState(issue.linearIssueId, targetState);
	await this.commentOnCompletedIssueReopen(issue, linear);