chore: add GitHub issue templates

Bug report template (includes gbrain doctor --json field) and
feature request template.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,27 @@
+---
+name: Bug Report
+about: Something isn't working
+labels: bug
+---
+
+**What happened?**
+
+
+**What did you expect?**
+
+
+**Steps to reproduce**
+1.
+2.
+3.
+
+**Environment**
+- gbrain version: (`gbrain version`)
+- OS:
+- Bun version: (`bun --version`)
+- Database: Supabase / self-hosted Postgres
+
+**`gbrain doctor --json` output**
+```json
+(paste output here)
+```

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,14 @@
+---
+name: Feature Request
+about: Suggest an improvement
+labels: enhancement
+---
+
+**What problem does this solve?**
+
+
+**What does the solution look like?**
+
+
+**Alternatives considered**
+

.gitignore

@@ -5,3 +5,4 @@ bin/
 .env.testing
 .18a49dfd730ff378-00000000.bun-build
 .18a49f9dfb996f70-00000000.bun-build
+.gstack/