Reduce CEL collection adaptation allocation

[snazy]

Avoid eager list, primitive-array, and repeated unsigned protobuf materialization on value adaptation and field access. Return interpreter-built CEL maps directly and fast-path already adapted CEL maps to skip redundant wrapping work. Add a lazy protobuf map field view so indexed lookup no longer builds a full Java map for every field read.

Area	Before	After	Result
nativeToValue(ArrayList) at 1k entries	4048 B/op, 0.998 us/op	32 B/op, 0.008 us/op	Fixed via list-backed ListT.
nativeToValue(ListValue) at 1k entries	4048 B/op, 1.024 us/op	32 B/op, 0.013 us/op	Fixed via list-backed ListT.
nativeToValue(int[]) at 1k entries	28200 B/op, 5.331 us/op	32 B/op, 0.008 us/op	Fixed via primitive-array-backed ListT.
nativeToValue(long[]) at 1k entries	28200 B/op, 5.559 us/op	32 B/op, 0.007 us/op	Fixed via primitive-array-backed ListT.
nativeToValue(double[]) at 1k entries	28248 B/op, 6.268 us/op	32 B/op, 0.008 us/op	Fixed via primitive-array-backed ListT.
nativeToValue(Map<Val, Val>) at 1k entries	95304 B/op, 31.331 us/op	24 B/op, 2.189 us/op	Fixed via already-CEL map fast path.
Dynamic map literal	1144 B/op, 0.331 us/op	664 B/op, 0.166 us/op	Fixed via direct wrapped-map construction.
Java ArrayList.exists() early match at 1k entries	4320 B/op, 0.893 us/op	304 B/op, 0.129 us/op	Fixed by avoiding eager input copy.
Java int[].exists() early match at 1k entries	28472 B/op, 6.359 us/op	304 B/op, 0.109 us/op	Fixed by avoiding eager primitive boxing.
Java map lookup at 1k entries	104 B/op, 0.048 us/op	104 B/op, 0.063 us/op	No generic lazy-map rewrite; normal lookup was already allocation-flat.
Protobuf map lookup at 1k entries	79488 B/op, 29.683 us/op	31320 B/op, 33.275 us/op	Allocation reduced by lazy protobuf map view; CPU roughly neutral/slower in this short run because lookup scans entries.
Protobuf repeated unsigned exists() early match at 1k entries	43592 B/op, 11.079 us/op	640 B/op, 0.238 us/op	Fixed via lazy unsigned list.
Protobuf repeated unsigned exists() late match at 1k entries	339218 B/op, 134.378 us/op	296202 B/op, 108.904 us/op	Improved, but still dominated by per-element wrapping during full scan.

[XN137]

could this be an optimized variant of find without having to convert the entry value?

nit: the method parameter should be called key to avoid confusion

[snazy]

Issue is that find() returns a Val - and errors are communicated as Err instances.

[XN137]

but here we are only checking != null ?
or are you saying checking whether the map contains a key should also fail when reading the value behind the key causes an error?