Refactor entity detail facet aggregation

[ktsaou]

Summary

• share category and maintainer aggregation across country and ASN detail builders
• keep country-specific ASN rollups and ASN-specific country distributions separate
• reduce source-only duplication in backend entity detail code

Validation

• go test ./pkg/engine
• go test -coverprofile=/tmp/update-ipsets-engine-slice26.cover -covermode=atomic ./pkg/engine
• go run ./tools/archposture -root . > /tmp/update-ipsets-archposture-slice26.json
• npx --yes jscpd@4.2.4 --reporters json,console --output /tmp/update-ipsets-jscpd-slice26-after --exitCode 0 --min-lines 20 --min-tokens 120 --max-lines 2000 --max-size 512kb --ignore "/*_test.go,pkg/web/static/,ui/dist/,ui/node_modules/,.agents/,tools/archposture/testdata/" cmd internal pkg tools ui/src .github/scripts
• make lint
• make staticcheck
• make golangci-lint
• CI=true make coverage
• make test-strict
• git diff --check

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics -4 complexity · -2 duplication

Metric	Results
Complexity	-4
Duplication	-2

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AI Reviewer: first review requested successfully. AI can make mistakes. Always validate suggestions.

_{TIP This summary will be updated as you push new changes.}