feat(postcodes/SV): bulk-import 262 El Salvador postcodes via Correos de El Salvador (#1039)

[dr5hn]

Summary

Adds 262 El Salvador postcodes spanning all 14 departments, sourced
from the 2025 Correos de El Salvador catalogue redistributed via the
micryptosv/SV-Postales-2025-API CSV.

• Coverage: 100% department resolution.
• Granularity: distrito level — one record per
  (4-digit code, distrito + municipio) pair.

How it works

The source ships codes in a 5-digit form (e.g. 02103) where the
always-present leading 0 is a regional grouping prefix. The
importer strips it to obtain the canonical 4-digit form expected by
the country regex ^(?:CP)*(\d{4})$.

Source & licence

• Source URL: https://raw.githubusercontent.com/micryptosv/SV-Postales-2025-API/main/data/elsalvador.csv
• Origin: 2025 Correos de El Salvador publicly published catalogue.
• Each row: "source": "correos-el-salvador-via-micryptosv"

Validation

• python3 -m py_compile clean.
• 100% of 262 codes match country.postal_code_regex (^(?:CP)*(\d{4})$).
• 100% of records resolve a valid state_id whose country_id == 66
  and whose iso2 matches state_code.
• No auto-managed fields (id, created_at, updated_at, flag).

Test plan

• Importer compiles and runs on a clean checkout.
• Cross-reference validator passes (regex + FK + state_code agreement).
• Idempotent merge verified.
• CI pipeline green.

Refs #1039.

🤖 Generated with Claude Code

[github-actions]

CSC Validation Report

PR Format

• ✅ Description provided
• ✅ Data source linked
• ✅ Issue linked (recommended for data changes)
• ✅ Justification / context provided

Labels applied: data:postcodes

Schema Validation (262 records)

✅ All records passed validation

Cross-Reference Validation

✅ 524 reference(s) verified

Source URL Verification

✅ 2 source URL(s) accessible

---

✅ All checks passed | Status: Ready for review

[Copilot]

Pull request overview

Adds El Salvador (SV) postcode coverage to the contributions/postcodes/ dataset and introduces a helper importer script to (re)generate/merge the SV postcode file from an upstream CSV source.

Changes:

• Add contributions/postcodes/SV.json with El Salvador postcodes keyed to SV departments (state_id/state_code).
• Add bin/scripts/sync/import_el_salvador_postcodes.py to fetch/parse the upstream CSV and write/merge SV postcodes idempotently.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated no comments.

File	Description
contributions/postcodes/SV.json	New SV postcode contribution dataset (country/state-linked records).
bin/scripts/sync/import_el_salvador_postcodes.py	New importer to fetch the upstream CSV, validate/transform codes, resolve state_id, and write/merge SV.json.