v0.7.1, session cache

What changed for looot customers in v0.7.1.

• Sessions are now cached by token kind, which made the dashboard noticeably faster: /connections loads in 1.25 seconds (was 2.1) and /usage in under 1 second (was about 1.7), measured in a browser.
• GET /v1/connections now carries each connection’s latest test receipt.