Make RuntimeUsageFilter package heuristic configurable (opt-in) + parameterized advice filter

[marceltft]

Summary

Makes the Appian fork's false-positive filtering configurable and generic, so it can be maintained on appian/main and contributed upstream without hardcoded Appian assumptions.

Sourced from the appian fork so the contribution is attributed to Appian.

Changes

1. Configurable runtime-usage package heuristic (runtimeUsage { packageHeuristic { ... } }, opt-in, disabled by default). Removes hardcoded appian-/eng- prefixes, appian-libraries path assumption, and appian/libraries stopwords — all now configuration. Also fixes that the heuristic was previously constructed but never invoked.
2. Parameterized advice coordinate filter (advice { includeCoordinates(...); excludeCoordinates(...) }) — pure regex over dependency coordinates, applied to all advice. Enables internal-only reports without any hardcoded group names.
3. Configurable transitive-exposure depth (advice { transitiveDepth(N) }, default 1) — bounded BFS over the reverse dependency graph to catch multi-hop transitive usage.
4. generateBuildHealth directory fix — feed the filtered-advice directory's *.json contents (not the directory) to GenerateBuildHealthTask, fixing a FileNotFoundException on the 3.19.x base.

De-Appianization

No Appian-specific strings remain in the plugin source. Reproduce the old hardcoded behavior via config:

dependencyAnalysis {
  runtimeUsage { packageHeuristic { enabled(true); stripPrefixes('appian-','eng-'); skipLeadingSegments(1); stopwords('appian','libraries') } }
  advice { includeCoordinates('^:.*', '^com\\.appian.*'); transitiveDepth(2) }
}

Testing

• Unit: FilterTransitiveExposureTest (8), RuntimeUsageFilterTest (10) — 0 failures.
• Validated end-to-end on ae master (759 projects): filters run correctly; internal-only filter reduces external advice to 0; transitive-depth sweep behaves as expected (depth 1→2 catches ~17% more real false positives, curve flattens by depth 3).

Note: our earlier ConcurrentModificationException patch was dropped during the rebase — main (3.19.x) already fixes it (iterator-based, in AndroidTransform).