perf: expand Encode() type switch with more common types

[xe-nvdk]

Problem

Every type not in the Encode() type switch hits reflect.ValueOf(v) which boxes on the heap + getEncoder() sync.Map lookup. Currently covered: nil, string, []byte, int, int64, uint, uint64, bool, float32, float64, time.Duration, time.Time, map[string]string, map[string]interface{}, []interface{}.

Proposal

Add more common types to the switch:

• int8, int16, int32
• uint8, uint16, uint32
• []string
• map[string]bool
• []byte fast path (if not already optimal)

Each addition eliminates reflect.ValueOf boxing + sync.Map lookup for that type.

Files

• encode.go — Encode() method type switch

Expected Impact

MEDIUM — depends on Arc's type distribution. Each added type eliminates 1 reflect.ValueOf + 1 sync.Map load per encode call of that type.