fix(linker): escape metadata strings and emit @defer block dependencies - #618

Summary

Two linker bugs that change the code it emits for partial declarations.

Strings written without escaping

Several metadata strings were put between quotes as they came:

• pipe name
• host.classAttribute (each class)
• controlCreate.passThroughInput
• attribute values in selector
• quoted inputs keys ("a.b")

A quote, backslash or newline in any of them broke the output, or turned part of the string into code:

// input
i0.ɵɵngDeclarePipe({ ..., name: 'a"+x+"' })
// before
i0.ɵɵdefinePipe({ name: "a"+x+"", type: P, pure: true })
// after
i0.ɵɵdefinePipe({ name: "a\"+x+\"", type: P, pure: true })

They now go through escape_string, like the other strings the linker already emits (host.attributes, styleAttribute).

deferBlockDependencies ignored

The linker never read deferBlockDependencies, so a linked @defer block got no dependency function (ɵɵdefer(1, 0)) and its lazy import() was dropped. A library that uses @defer with lazy dependencies rendered the deferred component as an unknown element.

Each entry is now matched to its @defer block in the order the binder lists them (getDeferBlocks()), as createR3ComponentDeferMetadata does in the TS linker. A null entry, or a block past the end of the list, gets no dependency function. The functions go through IngestOptions::defer_blocks into the existing PerBlock path and are emitted as written.

// input
template: "@defer { <lazy-cmp/> }",
deferBlockDependencies: [() => [import("./lazy").then(m => m.LazyCmp)]]
// before
i0.ɵɵdefer(1, 0);
// after
const C_Defer_1_DepsFn = () => [import("./lazy").then(m => m.LazyCmp)];
i0.ɵɵdefer(1, 0, C_Defer_1_DepsFn);

Tests

• test_link_escapes_metadata_strings: each of the five fields above with a quote in it, including passThroughInput (ɵɵControlFeature("f\"+x+\"")).
• test_link_defer_block_dependencies: nested blocks, a block inside @placeholder and a null entry. The expected fragments are the Angular linker's output for the same input (@angular/compiler-cli 22.2.3 Babel plugin, @angular/compiler 22.2.2).
• cargo test --all-features passes, and conformance is 1264/1264 with no snapshot change.