feat(proto): Add CreateLocationEnergySource RPC

[devsjc]

This adds a new RPC, CreateLocationEnergySource. Currently, there is no
way to add a new energy source (e.g. Wind) to an existing location
(which is an energy source + geometry combination). This rectifies that
lack, and also modifies create location such that it prevents creating
an existing one.### Contribution Checklist

• Have you followed the Open Climate Fix Contribution Guidelines?
• Have you referenced the Issue this PR addresses, where applicable?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added a summary of the changes?
• Have you written new tests for your changes, where applicable?
• Have you successfully run make lint with your changes locally?
• Have you successfully run make test with your changes locally?

Warning

PRs may be closed if all the above boxes are not checked.

[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":"2026-08-20T10:43:25Z","message":"Completed migrations"}
goos: linux
goarch: amd64
pkg: github.com/openclimatefix/data-platform/internal/server/postgres
cpu: INTEL(R) XEON(R) PLATINUM 8573C
BenchmarkPostgresClient/small/GetForecastAsTimeseries-4         	     174	   6464702 ns/op
BenchmarkPostgresClient/small/GetForecastAtTimestamp-4          	     366	   3036271 ns/op
BenchmarkPostgresClient/small/GetObservationsAsTimeseries-4     	    1119	   1031265 ns/op
BenchmarkPostgresClient/small/CreateForecast-4                  	     422	   2678311 ns/op
BenchmarkPostgresClient/small/StreamForecastData-4              	      37	  31436424 ns/op
PASS
ok  	github.com/openclimatefix/data-platform/internal/server/postgres	46.099s
?   	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 │
                                                   │     sec/op     │
PostgresClient/small/GetForecastAsTimeseries-4         8.146m ± ∞ ¹
PostgresClient/small/GetForecastAtTimestamp-4          3.556m ± ∞ ¹
PostgresClient/small/GetObservationsAsTimeseries-4     1.187m ± ∞ ¹
PostgresClient/small/CreateForecast-4                  3.192m ± ∞ ¹
PostgresClient/small/StreamForecastData-4              42.37m ± ∞ ¹
geomean                                                5.414m
¹ need >= 6 samples for confidence interval at level 0.95

cpu: INTEL(R) XEON(R) PLATINUM 8573C
                                                   │ bench-devsjc-create-location-source.txt │
                                                   │                 sec/op                  │
PostgresClient/small/GetForecastAsTimeseries-4                                  6.465m ± ∞ ¹
PostgresClient/small/GetForecastAtTimestamp-4                                   3.036m ± ∞ ¹
PostgresClient/small/GetObservationsAsTimeseries-4                              1.031m ± ∞ ¹
PostgresClient/small/CreateForecast-4                                           2.678m ± ∞ ¹
PostgresClient/small/StreamForecastData-4                                       31.44m ± ∞ ¹
geomean                                                                         4.429m
¹ need >= 6 samples for confidence interval at level 0.95