Add a troubleshooting page to each template's docs #81

Launch traffic will hit the same handful of first-run problems. A short reference page per template answers them before they turn into issues.

Phase 1: The pages

• reference/troubleshooting.mdx for each template: port already in use, dev certificates, SDK version refused by the template constraint, Docker not running, the SQLite file locked, --include-auth without --authority
• Template-specific entries (Nitro, the MCP Inspector, the Lambda emulator)
• Link it from SUPPORT.md and each getting-started page

Checks: the site builds, and each fix has been tried on a freshly generated solution.