Move triage instructions to a gemini skill

.gemini/skills/triage/SKILL.md

@@ -0,0 +1,21 @@
+---
+name: triage-helper
+description: Assistance with triage of unprioritized issues. Use when the user asks for help with triage.
+---
+
+When a user asks for help in the CLI:
+- Find the latest open issues in the flutter/flutter-intellij repo that don't have a priority label.
+- (Prompt the user for their personal access token if needed)
+- Consider the most recently updated issues first. Start presenting issues one at a time to the user, with the issue URL and other relevant information.
+- For each issue, give suggestions such as:
+    - Close the issue if it's not relevant anymore (e.g. it's been fixed, the code it's referencing is outdated, etc.)
+    - Suggest how to reproduce if it looks like it may be easy to reproduce locally
+    - Ask for a reproduction with a small project if reproduction may be hard locally
+    - Ask for more information and apply a waiting for response label
+    - Note a code pointer for the issue if it could be a good first issue for an external contributor
+    - Suggest a priority and other labels that may be relevant along with reasoning for the priority
+- Then wait for user feedback before continuing on to the next issue.
+
+
+
+Avoid executing tasks on GitHub directly, such as making comments, applying labels, or closing issues.