Add issue templates, support routing, and a triage label set

[AgentKush]

Hey Jim — small quality-of-life contribution to help manage the issue tracker. All additive, nothing existing is touched.

What's in here (all under .github/):

• ISSUE_TEMPLATE/bug_report.yml — a structured bug form that asks for version, OS, which part (Mod Manager / Editor / Downloads / Merge / in-game), repro steps, and — most usefully — a DebugLog.txt paste field. Should cut down the back-and-forth on reports that arrive with no version or log.
• ISSUE_TEMPLATE/feature_request.yml — a simple feature-request form.
• ISSUE_TEMPLATE/config.yml — routes "how do I install/download mods?" type questions to the Discord, the instruction video, and the README instead of the bug tracker. It sets blank_issues_enabled: false; if you'd rather keep the blank-issue option, just flip that one line to true.
• labels.yml + workflows/labels.yml — a triage label set (area / type / platform / priority) on top of your existing default labels. It's add-only (won't delete or rename anything you have). To create them: Actions tab → "Sync labels" → Run workflow (it only runs when you click it — nothing runs automatically).

Labels it adds: area: mod manager, area: mod editor, area: downloads & database, area: merge, area: mod content, crash, support, needs info, needs repro, upstream, translation / non-english, platform: linux, priority: high.

Totally fine to cherry-pick — take the templates and skip the labels, or vice-versa. 👍