A stored spell (probably) has the same range as the normal version of that spell
There is nothing in Glyph of Warding's text that explicitly states a maximum or minimum range at which it can cast a spell. The Range for Glyph of Warding itself is "Touch", but that is presumably to create the Glyph, not for effects the Glyph creates. The Glyph itself can "cover an area up to 10 feet in diameter", but that does not necessarily mean its effects are limited to this area.
There is a small hint in the text that the Glyph can effect things which are not touching it. Specifically, amongst the possible triggers it states (PHB, p. 245 bold added)
typical triggers include touching or standing on the glyph, removing another object covering the glyph, [or] approaching within a certain distance of the glyph.
However, this does not tell us definitively whether or not the Spell Glyph can cause effects at any particular range. After all, the the Explosive Runes version of Glyph of Warding effects things in a 20 foot radius sphere centered on the Glyph, so a trigger of "when a creature comes within 15 feet of the Glyph" would be a reasonable (if often sub-optimal) trigger for that feature alone.
The biggest hint we have is simply the description of what happens when a Spell Glyph is triggered (PHB, p. 246, bold added):
The spell being stored has no immediate effect when cast in this way. When the glyph is triggered, the stored spell is cast. If the spell has a target, it targets the creature that triggered the glyph.
The triggering of the glyph will cast the spell you stored in it, in your case Greater Restoration. The spell will have all the qualities that it usually does, including range, duration, and effects.1
If Glyph of Warding changed features of the spells it "casts", its text would say so. Since it does not, the Range of the stored spell most likely remains unchanged. So a creature would need to be touching the Glyph of Warding in order to benefit from a stored spell of Greater Restoration, since Greater Restoration's range is Touch. If the stored spell had a longer range, that range would be used instead. For example, if you stored the spell Haste into a Glyph of Warding, the Glyph could target any creature that triggered it with a Haste spell as long as that creature was within 30 feet of the Glyph (the range of Haste being 30 feet).
1: The only feature of the spell we can be sure will change when it is triggered (besides "concentration") is its components: the components are necessary for "casting" the spell (so you presumably needed them when you "cast the spell" as part of the casting of Glyph of Warding), but we are already told that "the stored spell is cast" when the glyph is triggered without any caveats (which is good, since the Glyph has no hands to gesture somatically or mouth to speak the verbal components). So the components will be unnecessary when the spell is triggered, the same way it would be unnecessary to pay gold for an item that a spell magically created, even though that item usually costs gold at a store.