fix(angular): error on unresolved templateUrl/styleUrl instead of silent passthrough

[mvanhorn]

Summary

An unresolved templateUrl or styleUrl now produces a hard error diagnostic (COMPONENT_RESOURCE_NOT_FOUND, naming the component class and the resource) instead of a silent passthrough. The diagnostic flows through the existing result.diagnostics -> NAPI result.errors path, so vite/esbuild builds fail loudly rather than shipping a class without its ɵcmp/ɵfac.

Why this matters

#314: when resource resolution fails, OXC returned the source unchanged - "the build 'succeeds,' ng dev/build prints no warning, and the breakage only shows up at runtime as an uninstantiable component." ngc raises a clear diagnostic in the same situation.

Two changes in crates/oxc_angular_compiler/src/component/transform.rs:

• the unresolved-templateUrl branch upgrades its vague warning ("Template URL '...' not found in resolved resources") to an error carrying the ngc-style code, the class name, and an explicit note that the component was emitted without its compiled definition
• resolve_styles now reports styleUrls that were missing from the provided resources (previously dropped silently), and each missing one surfaces the same COMPONENT_RESOURCE_NOT_FOUND error; when no resources are passed at all, style behavior is unchanged

This covers the loud-failure bar from the issue's "Required work" item 1. Item 2 (graceful folding of unresolvable ${...} template-literal references) is a separate codepath and is left for a follow-up so this stays reviewable.

Testing

• New unresolved_templateurl_is_a_hard_error and unresolved_styleurl_is_a_hard_error regression tests in class_metadata_resources_test.rs assert has_errors(), the error code, and that the message names the class and resource
• test_multi_component_external_template_unique_const_names now supplies its declared fab.css resource - under the new semantics its previously half-resolved fixture correctly errored, which is the behavior change working as intended
• Full cargo test -p oxc_angular_compiler: 2700 passed, 0 failed; cargo fmt --check clean
• The existing NAPI test should handle external template URLs with warning already asserts result.errors.length > 0 for the unresolved case and is unaffected (all diagnostics map to errors)

Fixes #314

[Brooooooklyn]

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[mvanhorn]

Good catch - this was real. Fixed in fd9d335: resolve_template now reports a missing templateUrl to the caller instead of falling back to the inline template when resources were provided, so the COMPONENT_RESOURCE_NOT_FOUND error fires for that shape too. Added a regression test (templateUrl + inline template + resources without the URL => diagnostic, inline not compiled). When no resource resolver is provided at all, the inline fallback is unchanged.