bayleaf-lti

LTI 1.1 / 1.3 connector spike. See issue #42.

• /health
• /lti/jwks (LTI 1.3 public JWKS)
• /lti/config.xml (LTI 1.1 cartridge for Canvas Add App > By URL)
• GET /lti/register (LTI 1.3 Dynamic Registration)
• /lti/login (OIDC initiation, stub)
• POST /lti/launch (auto-detects 1.1 vs 1.3)