fix(proto): Modify timestamp validation

[devsjc]

No description provided.

[github-actions]

Benchmark Results

Benchmark results

?   	github.com/openclimatefix/data-platform/cmd	[no test files]
?   	github.com/openclimatefix/data-platform/internal/gen/ocf/dp	[no test files]
?   	github.com/openclimatefix/data-platform/internal/interceptors	[no test files]
PASS
ok  	github.com/openclimatefix/data-platform/internal/server/dummy	0.005s
{"level":"debug","time":"2026-03-26T11:37:19Z","message":"Completed migrations"}
goos: linux
goarch: amd64
pkg: github.com/openclimatefix/data-platform/internal/server/postgres
cpu: AMD EPYC 7763 64-Core Processor                
BenchmarkPostgresClient/small/GetForecastAsTimeseries-4         	      63	  18280012 ns/op
BenchmarkPostgresClient/small/GetForecastAtTimestamp-4          	     266	   4283862 ns/op
BenchmarkPostgresClient/small/GetObservationsAsTimeseries-4     	     901	   1255386 ns/op
BenchmarkPostgresClient/small/CreateForecast-4                  	      87	  13383753 ns/op
PASS
ok  	github.com/openclimatefix/data-platform/internal/server/postgres	73.423s
?   	github.com/openclimatefix/data-platform/internal/server/postgres/gen	[no test files]

Benchmark vs base branch

goos: linux
goarch: amd64
pkg: github.com/openclimatefix/data-platform/internal/server/postgres
cpu: AMD EPYC 7763 64-Core Processor                
                                                   │ bench-main.txt │    bench-devsjc-protovalidate.txt    │
                                                   │     sec/op     │    sec/op     vs base                │
PostgresClient/small/GetForecastAsTimeseries-4         16.70m ± ∞ ¹   18.28m ± ∞ ¹       ~ (p=1.000 n=1) ²
PostgresClient/small/GetForecastAtTimestamp-4          3.995m ± ∞ ¹   4.284m ± ∞ ¹       ~ (p=1.000 n=1) ²
PostgresClient/small/GetObservationsAsTimeseries-4     1.204m ± ∞ ¹   1.255m ± ∞ ¹       ~ (p=1.000 n=1) ²
PostgresClient/small/CreateForecast-4                  12.90m ± ∞ ¹   13.38m ± ∞ ¹       ~ (p=1.000 n=1) ²
geomean                                                5.674m         6.023m        +6.15%
¹ need >= 6 samples for confidence interval at level 0.95
² need >= 4 samples to detect a difference at alpha level 0.05