jsonsample emits the same flat path format as jsonrawpaths but with
actual JSON values at leaf nodes and compact JSON samples at type intro
lines (e.g., {Root:{"name":"pikachu","id":25,...}}). Output is auto-
coalesced: types deduplicated by key set, one sample per primitive type.
Updated coalescer to handle TypeName:Sample format in type intros,
using first { instead of last { for parsing (handles nested JSON braces).
Sample output is valid input for jsoncoalesce (idempotent round-trip).
Coalesce merges streamer output by deduplicating types with identical
key sets, collapsing {null} into nullable annotations ({string?}),
cleaning up type names (removing unnecessary numbers, deriving names
from keys when many types share a shape), and eliding duplicate type
definitions. Preserves {undefined} distinct from {null} per the
three-stage pipeline design.
Pokemon fixture: 241 raw lines → 140 coalesced lines.
