feat: add startup-business-analyst plugin

Comprehensive startup analysis plugin with market sizing, financial modeling, team planning, and strategic research for early-stage companies.

- 5 skills: market sizing, financial modeling, team planning, competitive analysis, metrics
- 3 commands: market-opportunity, financial-projections, business-case
- 1 agent: startup-analyst
- Covers TAM/SAM/SOM, unit economics, competitive landscape, hiring plans

plugins/startup-business-analyst/.gitignore

@@ -0,0 +1,17 @@
+# Local configuration files
+.claude/*.local.md
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Editor files
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# Temporary files
+*.tmp
+*.log