Fix stale bot re-commenting on case-mismatched labels (#4394)

## Problem

The issue-lifecycle stale rule checked labels with case-sensitive
`Array.includes()`, so an issue carrying the `Stale` label (created by
the `actions/stale` PR bot) was never recognized as stale.
`hasStaleLabel` stayed `false` and the bot re-posted the 7-day warning
on **every** daily cron run.

Example: [#3441](https://github.com/openfrontio/OpenFrontIO/issues/3441)
got the same "hasn't had activity in 7 days" comment ~16 days in a row.

## Fix

GitHub label names are case-insensitive (you can't have both `Stale` and
`stale`), so the gate should be too. Adds a `hasLabel()` helper in
`github.ts` and routes all label checks through it (`STALE`,
`KEEP_OPEN`, `APPROVED`, `NOT_APPROVED`).

Now an issue gets one stale warning when marked, then silence until the
14-day close.

## Note

The Dependabot PR-exemption change (`pr-stale.yml`) is being applied
separately — the CI token here lacks `workflow` scope to push
workflow-file changes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

scripts/issue-lifecycle/github.ts

@@ -28,6 +28,14 @@ export function makeOctokit(token: string): Octokit {
   return new Octokit({ auth: token });
 }
 
+// GitHub label names are case-insensitive (you cannot have both "Stale" and
+// "stale"), so match them that way — otherwise a label applied with different
+// casing (e.g. the "Stale" label from the PR stale action) is missed.
+export function hasLabel(issue: Issue, label: string): boolean {
+  const target = label.toLowerCase();
+  return issue.labels.some((l) => l.toLowerCase() === target);
+}
+
 export function isBotUser(
   user: { login: string; type: string } | null,
 ): boolean {