fix: resolve the SonarCloud findings from the latest develop scan

[devin-ai-integration]

What and why

The latest SonarCloud analysis of develop fails its quality gate on new-code reliability and security, and reports 149 open findings. This resolves them, gate-breakers first and cognitive complexity last.

Gate breakers

• ProjectTextExporter.containsDocument compared Optional<String> with a String, so it was always false and two SysON resources with the same file name were exported under one name. Now name().filter(name::equals).isPresent(); a test pins the foo.sysml / foo-1.sysml outcome.
• Java client: Condition.equal(...) is renamed Condition.equalTo(...) (it shadowed Object.equals in every reader's eye). Callers, docs and a changelog fragment updated.
• The two SysON frontend workflow installs run npm ci --ignore-scripts (as the VS Code job already did), and install:syson passes --ignore-scripts too; the build needs no lifecycle scripts.

Other findings

• RunResult gets a Builder in place of its 14- and 13-argument constructors.
• Nested ternaries, deep nesting, unused props and duplicated literals across the SysON backend/frontend, the Java client, the migrate package, docpdf and the toolchain script are replaced with named constants and small helpers; diagnostic text is unchanged.
• RunVerdictSummaryTest moves to the directory of its package; FakeElement.getName delegates to getDeclaredName; unused imports, an unnecessary throws, blank-import comments, and print/any shadowing are cleaned up.
• The 17 Go and 1 Java functions flagged for cognitive complexity are split into cohesive helpers with no behaviour change; none is above Sonar's threshold now.
• .gitignore covers editors/syson/**/target/.

Intentionally left (recorded so the next scan is not a surprise): java:S1452 in syson-api-stubs mirrors the real Sirius signature and no IRepresentationEventProcessor stub exists; java:S6539 on Model is informational; java:S1165 on EditException.referrers cannot be final because readObject assigns it.

How it was verified

• go build ./..., go vet ./..., gofmt -l ., make lint, and go test ./... with all four OPENSYSML_REQUIRE_* corpus variables set.
• gocognit -over 15 over cmd/sysml and internal/translate/migrate: none of the flagged functions remain.
• client/java: mvn install; editors/syson/backend: mvn test (27 tests, including the new duplicate-name test).
• editors/syson/frontend: npm ci --ignore-scripts && npm run typecheck && npm run format:check && npm test && npm run build.
• python3 scripts/changelog.py check; bash -n on the toolchain script.
• The fUML driver under scripts/fuml-driver was syntax-checked with javac only; its Maven dependencies could not be downloaded here.

Checklist

• make test and make lint pass locally
• Tests added or updated for the change
• Documentation extended where it already covers the surface (see CONTRIBUTING.md)
• Changelog entry added as changes/unreleased/<slug>.<section>.md, not as an edit to CHANGELOG.md
• baselines regenerated and make docs-counts run if a gate count moved (compliance rows need nothing: the census is counted at docs build)
• No internal work-item labels (waves, slices, F4, K5) in the body, docs, or changelog

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring