Say what PageSize does on a roll-up

[kkdev92]

PageSize on RollUp and DailyRollUp does not bound the response. A roll-up returning 1,686
points returns the same 1,686 with PageSize set to 1440.

It bounds the query. Two checks use it, they round in opposite directions, and neither names it
when it refuses:

	Rule	Refusal
Ceiling, both operations	at most ⌊cap ÷ window⌋ — whole windows that fit the data type's range cap	INVALID_ROLLUP_QUERY_DURATION
Floor, DailyRollUp only	at least ⌈range ÷ window⌉ — windows needed to cover the range, a partial one counting as one	INVALID_DATA_POINT_NAME

The ceiling ignores the range asked for, so a one-day request is refused at the same boundary as a
ninety-day one.

Leaving PageSize unset satisfies both checks in most cases, because unset behaves as though it
were ⌈range ÷ window⌉. Not in all cases: that implied value is itself subject to the ceiling, so
a range needing more windows than the cap allows is refused with nothing set. On RollUp an
explicit value within the ceiling is then the way through, and the response is unaffected. On
DailyRollUp the two bounds leave no accepted value, and the combination cannot be requested at
all.

The property description both requests carry — a maximum number of points, 1440 by default — is
Google's own, reproduced as the generator found it. docs/data-points.md now records the observed
behaviour beside it, and semantics.json carries the same against both operations.

Scope

Documentation only. No generated file changes: codegen verify matches all committed sources byte
for byte.

Not claimed, because it was not established: nothing about heart-rate, which the credential used
could not read; and nothing about whether these operations ever page, only that no next page token
came back in anything tried.

🤖 Generated with Claude Code