Two changes on the Call hot path:
* Replace httpReq.Header.Set("Content-Type", "application/json") (and Accept) with direct map writes against a package-level []string. Both keys are already canonical so the canonicalising path inside Header.Set was pure overhead; saves the per-call []string{val} allocation x2.
* Add a bool fast-path in decodeResult: ~60% of Telegram methods return bool, and the API emits the envelope with no whitespace, so a bytes.Equal check against the two canonical bodies short-circuits the generic Result[bool] Unmarshal entirely. any(true).(Resp) does not box thanks to Go's static bool interface values.
Combined effect on Call_BoolResponse: 18 -> 14 allocs/op, 634ns -> 526ns. DecodeResult_Bool isolation bench: 50ns / 2 allocs -> 2.87ns / 0 allocs.
Hermetic benchmarks (no network) covering Call encode+decode, webhook ServeHTTP body parse, and Router dispatch (command/regex/filter). Use Go 1.24+ b.Loop() idiom. .benchstats/baseline.txt pins the pre-optimisation numbers for benchstat comparisons.
lukaszraczylo