chore: polish AgentMemora after npm launch

[halilneed]

Post-publish launch polish

• switches the README primary path to the published npx -y agentmemora@latest command
• adds npm version, CI and MIT badges for launch trust signals
• sharpens the first-fold positioning around memory intelligence
• adds a zero-commitment doctor command for first-time users
• removes the obsolete pre-publish GitHub install fallback
• normalizes the npm bin path to avoid the publish-time auto-correction warning on future releases

No product behavior or scanning semantics change.