feat(core/cbor): add single-pass cbor serde

[kuhe]

Add single-pass ShapeSerializer and ShapeDeserializer for CBOR, combining Smithy data-model prep with the encoding pass.

Serialization Results

Test Case	CBOR Size	JSON Size	CBOR multi ms	CBOR single ms	JSON ms	Single vs Multi	Single vs JSON
list<string(0,180)>	469 kb	482 kb	53 ms	24 ms	68 ms	2.19x	2.79x
list<float>	270 kb	675 kb	220 ms	27 ms	308 ms	8.24x	11.55x
list<int>	253 kb	458 kb	693 ms	92 ms	277 ms	7.54x	3.01x
list<long int>	250 kb	549 kb	360 ms	56 ms	245 ms	6.46x	4.40x
map<string, string>	438 kb	455 kb	42 ms	30 ms	75 ms	1.41x	2.54x
map<string, long int>	38 kb	49 kb	25 ms	12 ms	22 ms	2.08x	1.81x
list<struct> PutMetricData-like	363 kb	459 kb	344 ms	121 ms	385 ms	2.84x	3.17x
struct PutMetricData realistic	1.7 mb	2.2 mb	1846 ms	459 ms	1814 ms	4.02x	3.95x
list<struct> non-ASCII keys	399 kb	483 kb	239 ms	93 ms	280 ms	2.56x	3.00x
list<struct> with blobs	263 kb	353 kb	140 ms	70 ms	116 ms	2.01x	1.66x
list<struct> with timestamps	229 kb	345 kb	227 ms	83 ms	167 ms	2.75x	2.02x

Deserialization Results

Test Case	Data Size	CBOR multi ms	CBOR single ms	JSON ms	Single vs Multi	Single vs JSON
list<string(0,180)>	468 kb	34 ms	24 ms	25 ms	1.45x	1.08x
list<float>	270 kb	83 ms	32 ms	235 ms	2.57x	7.28x
list<int>	253 kb	246 ms	97 ms	311 ms	2.54x	3.21x
list<long int>	250 kb	126 ms	55 ms	194 ms	2.28x	3.52x
map<string, string>	439 kb	45 ms	37 ms	37 ms	1.21x	1.01x
map<string, long int>	38 kb	28 ms	21 ms	29 ms	1.33x	1.41x
list<struct> PutMetricData-like	363 kb	360 ms	163 ms	392 ms	2.21x	2.41x
struct PutMetricData realistic	1.7 mb	2082 ms	609 ms	2096 ms	3.42x	3.44x
list<struct> non-ASCII keys	399 kb	444 ms	133 ms	269 ms	3.33x	2.02x
list<struct> with blobs	263 kb	103 ms	54 ms	196 ms	1.92x	3.65x
list<struct> with timestamps	229 kb	203 ms	100 ms	208 ms	2.03x	2.07x