feat(error): init error handling philosophy

[guergabo]

Changes

Fixes #95
Fixes #96
Fixes #98
Fixes #99

Context

Error Duality

Expected Errors

1. application level errors (tolerable, expected, non-retryable) -> ResponseStatus && validation layer using json tags -- protobuf

2. platform level errors (tolerable, expected, retryable) -> errors.New() then convert to ResponseStatus at api layer

Unexpected Errors

1. catastrophic (intolerable, unexpected) -> panic()

[codecov]

Codecov Report

Attention: 155 lines in your changes are missing coverage. Please review.

Comparison is base (2c924b7) 67.16% compared to head (42a68a4) 68.61%.
Report is 4 commits behind head on main.

Files	Patch %	Lines
internal/app/subsystems/api/http/promise.go	23.07%	40 Missing ⚠️
internal/app/subsystems/api/service/service.go	45.45%	25 Missing and 5 partials ⚠️
internal/app/subsystems/api/grpc/api/promise.pb.go	6.89%	27 Missing ⚠️
internal/app/subsystems/api/grpc/grpc.go	73.68%	9 Missing and 1 partial ⚠️
internal/app/coroutines/cancelPromise.go	36.36%	7 Missing ⚠️
internal/kernel/t_api/status.go	91.42%	6 Missing ⚠️
internal/app/coroutines/createPromise.go	37.50%	5 Missing ⚠️
internal/app/coroutines/rejectPromise.go	44.44%	5 Missing ⚠️
internal/app/coroutines/resolvePromise.go	44.44%	5 Missing ⚠️
internal/app/coroutines/readPromise.go	33.33%	4 Missing ⚠️
... and 10 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #111      +/-   ##
==========================================
+ Coverage   67.16%   68.61%   +1.45%     
==========================================
  Files          57       61       +4     
  Lines        5944     6163     +219     
==========================================
+ Hits         3992     4229     +237     
+ Misses       1667     1654      -13     
+ Partials      285      280       -5     

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[guergabo]

@vaibhawvipul let's talk tmrrw about this pr. this changes a bit of the expected api behavior. for example introducing 409 status code and returning error messages for unsuccessful requests instead of nil or promises. the sdk will need to adjust a bit. additionally, the client deciding which errors are retryable becomes trivial once this is merged.

For grpc, we return proper grpc error codes now and status in response is only to capture dedup logic (a.k.a, did this request change something in the database or not).