Declare run expectations

Previous value: -"The run's complete set of expectations, declared ONCE at the start of the run -- criteria the ping BODY of THIS run's eventual success ping must satisfy when the run closes, checked instead of letting the run grade itself. IMMUTABLE: a second call for the same rid is rejected with a conflict error and the first declaration stands unchanged -- there is no way to edit, add to, or replace it once made, so decide the whole set before you start work. Declaring nothing is allowed and always has been: simply never call this tool for a run, and the monitor's own check-level assertions (if any) stay in force unchanged. INCLUDE AT LEAST ONE POSITIVE CRITERION -- a 'contains', 'matches' or 'json_path' entry -- in every declaration. A declaration made ENTIRELY of 'not_contains' entries is self-satisfying on empty output: a run that produces nothing at all still passes, because there is nothing for the pattern to find. That is precisely the evasion this feature exists to close, so a purely negative declaration defeats its own purpose. A 'matches' entry only counts as positive if its pattern REJECTS an empty body: '.*', '(?s).*' and '^$' all accept one and are validated as perfectly legal patterns, so a declaration resting on one of those is no better than a purely negative declaration. Supply a JSON ARRAY as a string, e.g. '[{\"kind\":\"json_path\",\"path\":\"result.rows_processed\",\"op\":\"gt\",\"value\":\"0\"}]'. Fields per entry: kind (required), value, path, op -- no name; a run's declared criteria have none, unlike a monitor's own output assertions. kind is one of 'contains' (body contains value as a substring), 'not_contains' (body does not contain it), 'matches' (body matches value as a Go RE2 regexp, max 1000 bytes), or 'json_path' (parse the body as JSON, read the value at path, compare it against value with op). contains/not_contains/matches require value; json_path requires path and op. path is a DOTTED path only ('a.b.c') -- the query syntax of a real JSONPath library ('[', '*', '$') is rejected. op is one of 'eq', 'ne', 'gt', 'gte', 'lt', 'lte'. At most 20 assertions per run. A malformed entry (uncompilable regexp, a path carrying query syntax, an unknown kind or op) is rejected before anything is written, and nothing is stored if any entry fails."New value: +"The run's complete criteria, as a JSON array string, e.g. '[{\"kind\":\"json_path\",\"path\":\"result.rows_processed\",\"op\":\"gt\",\"value\":\"0\"}]'. Fields: kind (required), value, path, op; no name. kind: contains, not_contains, matches (RE2, max 1000 bytes) or json_path (the value at a dotted path, e.g. 'a.b.c', compared with op: eq, ne, gt, gte, lt, lte). Only not_contains entries, or a matches pattern that accepts an empty body ('.*', '^$'), pass on empty output; a contains, json_path or empty-rejecting matches entry catches a run that produced nothing. At most 20; one malformed entry rejects the whole declaration. Runs with no declaration keep the monitor's own assertions."

Previous value: -"The run id exactly as sent on this run's /start ping — the same rid used on every step and the terminal ping."New value: +"The run id exactly as sent on this run's /start ping, the same rid used on every step and the terminal ping."