v1.8.4: fix deadlock on websocket failure

Changes

• Fixed deadlock due to sudden websocket error not canceling the whole goroutine group (#72, #74).
• Refactored the project to allow easier integration testing.
• Added contract testing to avoid API client implementation drift with FC2 API.
• Added check to avoid a watcher getting canceled without its parent getting canceled.

SHA256 Checksums

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b6b317ceb6250386b9e4dc228790c041ce5c24986541032453e4b95d82f63f04 fc2-live-dl-go-darwin-arm64
b7de2c9a768c74dfb3a94811db35ed6ecec21dddbe49a885436160a332157cd1 fc2-live-dl-go-linux-amd64
d5231159d4d4a64727acced7b2a25bb9489615a07199210d1118f57c976a68d3 fc2-live-dl-go-linux-arm64
4b8c29ba3b858154b6abd9eff52fe7dc8aab19c3b0ffb5d0f79c0dcd71461874 fc2-live-dl-go-linux-riscv64
dd56af9012ea2fd451afc625f002876b9a7db2ee16ac09165052c500b0547e5c fc2-live-dl-go-windows-amd64.exe

Full Changelog: v1.8.3...v1.8.4