[#835] Create BRP client

[stefanvi]

DOD checklist

This PR includes a first draft for querying the BRP and adds the docker personen mock service.

Open questions

• How do we validate a person's last name? BRP contains a 'partners' field with registered marriages. Perhaps we need to cross-validate against this to see if these conditions hold:

For PR maintainer

Perform these checks before marking the PR as ready:

• I have linked the PR to at least one issue.
• I assigned the PR to myself.
• I have added a description how to test this PR (see "Review Instructions").
• I have added documentation where necessary.

For reviewer

• I have read all code changes.
• I have audited the code quality.
• I have tested the changes either or both:
  • locally
  • on the test environment (preferred)
• I have validated that the PR is functionally correct (use-cases, figma designs, etc.)

Review instructions

insert a description on how to test this PR here

[github-actions]

PDF diff summary

Template	Input	Status
model-h1	model-h1-example-1.pdf	🔵 identical
model-h1	model-h1-example-2.pdf	🔵 identical
model-h1	model-h1-example-3.pdf	🔵 identical
model-h3-1	model-h3-1-example-1.pdf	🔵 identical
model-h3-1	model-h3-1-example-2.pdf	🔵 identical
model-h3-1	model-h3-1-example-3.pdf	🔵 identical
model-h3-2	model-h3-2-example-1.pdf	🔵 identical
model-h3-2	model-h3-2-example-2.pdf	🔵 identical
model-h3-2	model-h3-2-example-3.pdf	🔵 identical
model-h4	model-h4-example-1.pdf	🔵 identical
model-h4	model-h4-example-2.pdf	🔵 identical
model-h4	model-h4-example-3.pdf	🔵 identical
model-h9	model-h9-example-1.pdf	🔵 identical
model-h9	model-h9-example-2.pdf	🔵 identical
model-h9	model-h9-example-3.pdf	🔵 identical
model-i4	model-i4-example-1.pdf	🔵 identical
model-i4	model-i4-example-2.pdf	🔵 identical

[github-actions]

Sigrid maintainability feedback

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⏸️️ You are still below your objective of 3.5 stars.

Show details

Sigrid compared your code against the baseline of 2026-07-30.

👍 What went well?

You fixed or improved 0 refactoring candidates.

👎 What could be better?

Unfortunately, 17 refactoring candidates were introduced or got worse.

Risk	System property	Location
🔴	Unit Size (Introduced)	src/structs/brp/person.rs BrpPerson.from(BrpPersonRaw)
🔴	Unit Size (Worsened)	src/csb/store_csb/mod.rs CsbStoreData.apply(StoreEvent<CsbEvent>)
🔴	Unit Size (Introduced)	src/structs/brp/client.rs BrpClient.verify(Person,Vec<CandidateListId>)
🔴	Module Coupling (Worsened)	src/csb/store_csb/getters.rs
🟠	Unit Size (Worsened)	src/state.rs AppState.new_with_config(Config)
🟠	Unit Size (Worsened)	src/core/config.rs Config.from_env_with(F)
🟠	Unit Size (Worsened)	src/csb/import/pages/import.rs do_import(AppState,ImportForm,Locale)
🟠	Unit Size (Introduced)	src/csb/import/pages/import.rs verify_candidates(Store<CsbStoreData>,BrpClient)
⚪️		+ 9 more

📚 Remaining technical debt

7 refactoring candidates didn't get better or worse, but are still present in the code you touched.

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⭐️ Sigrid ratings

System property	System on 2026-07-30	Before changes	New/changed code
Volume	N/A	N/A	N/A
Duplication	5.3	5.5	5.5
Unit Size	3.1	2.6	1.9
Unit Complexity	4.5	4.2	2.7
Unit Interfacing	2.4	2.8	3.9
Module Coupling	3.0	1.1	1.8
Component Independence	1.9	N/A	N/A
Component Entanglement	1.6	N/A	N/A
Maintainability	3.1	2.7	2.6

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[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
88.7% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud