feat: add error handling for agent callbacks

[m8vago]

• Add a proto function for reporting agent command errors
• Report container not found errors

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 8.49057% with 194 lines in your changes are missing coverage. Please review.

Project coverage is 17.90%. Comparing base (5ca501c) to head (acc1c3d).

Files	Patch %	Lines
golang/internal/grpc/grpc.go	0.00%	119 Missing :warning:
web/crux/src/grpc/protobuf/proto/agent.ts	9.09%	20 Missing :warning:
web/crux/src/app/agent/agent.service.ts	12.50%	14 Missing :warning:
web/crux/src/domain/agent-callback.ts	50.00%	14 Missing :warning:
golang/pkg/dagent/utils/docker.go	0.00%	12 Missing :warning:
golang/pkg/dagent/utils/dockerhelper.go	0.00%	5 Missing :warning:
web/crux/src/domain/agent.ts	0.00%	5 Missing :warning:
golang/pkg/crane/k8s/log.go	0.00%	3 Missing :warning:
web/crux/src/app/agent/agent.grpc.controller.ts	0.00%	2 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #944 +/- ## =========================================== - Coverage 17.99% 17.90% -0.10% =========================================== Files 350 350 Lines 17606 17731 +125 Branches 1029 1039 +10 =========================================== + Hits 3169 3174 +5 - Misses 14249 14369 +120 Partials 188 188 ```

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