fix: preserve object and array spread syntax in template bindings

[ashley-hunter]

Summary

Object and array spread expressions in Angular template bindings were silently dropped during compilation with no error or warning:

<!-- Before: spread lost, emits { extra: 'val' } -->
<div [prop]="{ ...base, extra: 'val' }"></div>

<!-- After: correctly emits pureFunction1(_c0, ctx.base) where _c0 = (a0) => ({ ...a0, extra: 'val' }) -->
<div [prop]="{ ...base, extra: 'val' }"></div>

The root cause was that LiteralMapKey::Spread was skipped in ingest.rs during AST→IR conversion, and no subsequent pipeline stage had any representation for spread entries. Array spread ([...a, 'val']) had the same gap in angular_expression.rs.

Changes

The fix spans the full compilation pipeline:

• ir/expression.rs: Added spreads: Vec<bool> parallel field to IrLiteralMapExpr, DerivedLiteralMapExpr, IrLiteralArrayExpr, DerivedLiteralArrayExpr to track which entries are spreads
• pipeline/ingest.rs: Handle LiteralMapKey::Spread when converting AST→IR (previously skipped with a comment)
• pipeline/phases/resolve_names.rs: Propagate spreads through name resolution
• pipeline/phases/pure_literal_structures.rs: Emit spread entries in pure function wrappers
• pipeline/phases/reify/ir_expression.rs: Emit spread entries when lowering IR→output AST
• pipeline/phases/reify/angular_expression.rs: Handle SpreadElement in LiteralArray arm
• pipeline/emit.rs: Fix convert_ast_for_pure_function_body to handle spreads in both LiteralMap and LiteralArray
• output/ast.rs: clone_in correctly copies is_spread on LiteralMapEntry
• output/emitter.rs: Emit ...expr for spread entries in both object and array literals
• output/oxc_converter.rs: Handle SpreadProperty in object expressions (previously skipped)
• pipeline/phases/chaining.rs: Preserve is_spread when cloning entries during chaining
• pipeline/phases/defer_configs.rs, pipe_variadic.rs: Maintain spreads parallel-vec invariant

Tests

• 9 new Rust snapshot tests: object spread, array spread, multiple spreads, spread-with-pipe, spread-at-end, chained bindings, arrow function body spread
• 1 new unit test in oxc_converter.rs for the SpreadProperty path
• 2 new TypeScript NAPI tests for object and array spread

Output verified against official Angular 21.2.11 compiler — functionally identical (pure function wrapping, parameter naming, binding instructions).

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