[12] feat(angular): model declarative template and stylesheet assets

[fernandofielmann]

Goal

Reuse Asset and LOADS_ASSET for resources referenced declaratively by Angular templates and stylesheets.

Scope

• Extract static template src and href asset references.
• Extract component styleUrls and CSS/SCSS url(...) references.
• Resolve paths relative to the template/stylesheet/component conservatively.
• Add source: template|stylesheet and reference-kind metadata to LOADS_ASSET.
• Deduplicate references without merging distinct source locations.
• Keep assets out of HTTP route matching, HTTP_CALLS, DATA_FLOWS, navigation, and cross_service.
• Continue honoring discovery exclusions for binary/minified files while retaining graph references where appropriate.

Dependencies

• Depends on: [09] feat(angular): link templates, selectors, and bindings #16 ([09] template/component linkage).
• Existing prerequisite already merged: frontend Asset/LOADS_ASSET model from PR feat(typescript): model frontend asset loads #4.

Acceptance criteria

• Static template and stylesheet references create or reuse the correct Asset node.
• Relative and root-relative paths resolve deterministically.
• Data URLs, external URLs, dynamic bindings, and ambiguous paths are handled conservatively.
• Assets never appear as HTTP or navigation routes.
• Sequential and parallel pipelines emit equivalent asset relationships.
• Schema and README document new source/reference metadata.

Validation

• Add HTML, inline/external CSS/SCSS, relative path, external/data URL, ambiguity, deduplication, and parity fixtures.
• Run asset, route, Angular, and edge suites, lint-ci, and scripts/test.sh.