fix(angular): fix 7 compiler divergences from Angular reference

[Brooooooklyn]

1. Add missing @switch validation: report errors for non-block children,
   enforce exactly one @case parameter, single @default, and no @default
   parameters
2. Carry viewport trigger options through ingest into DeferOnOp IR
3. Change generateArrowFunctions phase to Kind::Both with host support
4. Add view.functions traversal to next_context_merging phase
5. Remove incorrect @default reorder in @switch ingest (preserve source order)
6. Emit null arg for unresolved target slots in defer reify (viewport,
   interaction, hover triggers)
7. Add debug_assert for unexpected multi-line arrow functions

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com

---

Note

Medium Risk
Touches multiple compilation phases and changes emitted instruction arguments and validation behavior; while well-scoped with tests/snapshots, it can subtly affect generated output and compatibility across templates/host bindings.

Overview
Improves Angular-compatibility by tightening @switch parsing: non-@case/@default children now error, @case must have exactly one parameter, and @default is limited to one block with no parameters; new tests cover these validations.

Adjusts codegen/IR to better match Angular output: @switch ingestion now explicitly reorders the @default group to the end for consistent slot/function naming, viewport defer triggers now carry options through IR, and defer trigger reify always emits a first argument (slot or null) for viewport/interaction/hover (updating snapshots like ɵɵdeferOnViewport(null)).

Extends pipeline behavior to host compilation and arrow-function internals: generateArrowFunctions now runs for both template and host jobs (new host variant), multi-line template arrow functions are debug-asserted as impossible, and mergeNextContextExpressions now also traverses arrow-function ops lists via view.functions.

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[Brooooooklyn]

• fix(angular): fix 7 compiler divergences from Angular reference #26 👈 (View in Graphite)
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