I can only talk about what happens at my school (where I'm an administrator)
First of all, there's a bunch of things that happen in the course of the school day that aren't particularly academic, and sort of naturally accomodate different level learners: Each day our K kids get the following:
45 or 90 minutes of arts instruction -- dance, music, art, Spanish, PE, some of them twice.
an hour of recess
45 minutes of choice time (a mixture of academic choices like reading in the library center which would include some picture books that are sophisticated enough that your daughter would probably enjoy them, and choices like building with blocks).
45 minutes of lunch and snack
15 minutes of morning meeting (greet your friends, review the schedule, read a morning message (which would be written too low for your daughter, but which takes about 3 minutes), play a movement game).
Altogether that's a little more than 1/2 of the day.
Then the kids get the following:
30 minutes writer's workshop -- there's a 5 minute mini lesson which would probably be pretty boring for your daughter, but the rest of it is kids writing on whatever level they're on and the teacher circulating and giving kids coaching on the next steps for them -- so for your daughter it might be character development, while the kid next door gets "you can write the first letter of the names of the people in your picture". Our kids who are far above grade level do pretty well with this.
30 minutes of reading workshop -- again a mini lesson that would be boring but brief, then independent reading -- during the first part of the year the kids are officially working on retelling familiar stories, looking through nonfiction books and learning from the pictures, etc . . . The kid who can read generally just read the books. Books are chosen based on their "retellability" not their reading level so there's a wide range of challenge. Then partner reading where a child sits with a child with similar reading level (although your child would likely have a partner who reads at a lower level since her skills are so high) and take turns telling each other about what they read that day and reading to each other. Later in the year kids are reading books that are "just right" for them, that is books that correspond to the reading level they test at, but the format (read by yourself, then talk with a partner) is the same. They also meet with the teacher 1 to 4 times a week for about 10 minutes to talk about new books and get some coaching -- these are ability grouped and your child would probably meet once by herself.
30 minutes of math workshop -- would be far below her level, whether she'd find it boring really depends. There's a lot of creating with manipulatives, a lot of playing simple strategy games. Many of our gifted kids find it a fun social time, and some kids, even kids who are only slightly behind, may find it boring -- it depends really on how flexible and easy going they are.
20 minutes of phonics/sight words -- there's some effort to differentiate here, but this is probably one of the times most likely to bore a bright/high performing child. Again there's some differentiation -- in our higher grade the highest kids skip this and do research projects, but unfortunately phonics isn't something beginning readers can do independently -- you need someone there to tell you the sounds of the letters, model, etc . . . So the kids who don't need it either end up playing/working along side the others or doing some kind of seat work -- the teacher might let a kid read independently.
20 minutes or read aloud -- often includes content that's new, even for a pretty sophisticated kid. E.g. our kids do a unit on heroes from Black History, so kids might be listening to a picture biography of Bessie Coleman that they've never heard before. Or it could be fun poetry that would make any kid laugh.
20 minutes of "fine motor" -- playing with playdough, making things with materials that require kids to use their finger tips to manipulate, building letters with manipulatives. includes handwriting worksheets a couple of times a week (these are the only worksheets we do)
Science/Social studies -- 45 minutes a couple of times a week, might be planting plants or doing a simple experiment. Again it's probably a mix of things that will be easy (e.g reading rebus directions for an experiment) and things that involve new learning.
The rest is sort of a mishmash -- maybe they're writing thank you notes for the person who led their field trip, or getting their wiggles out with a game.
In my experience the kids at the top have a decent experience in K. About 1/2 the day has nothing to do with academics and they're fine. About another 1/4 is pretty naturally differentiated or new information. How they react to the last quarter really really depends on the kid. Many kids, including bright kids, enjoy playing and manipulating and being with friends and find a lot of these activities fun even if they aren't challenging (e.g. planting seeds -- do all K need to do this? no many are already familiar with it. But then my 60 year old mother knows how it works, but still enjoys working in the garden). There also a minority, not neccessarily any brighter, kids who find any kind of review "boring" and get restless very easily. They struggle. I think it's important to note that this is as much about temperment as it is about intelligence/academic skills. The kids with low skills and similar temperments struggle the second something's confusing. The kids with average skills and similar temperment struggle if they're momentarily behind because they were absent yesterday, or if they mastered it yesterday and it's now "easy" for them.
I'm going to add that there are plenty of schools like PP's posted where kids color all day -- the reality is that all the kids are coloring and doing worksheets all day and that's not appropriate for any child. The gifted or advanced child might find it even harder, but I'd wouldn't wish those schools on anyone's child.
OP: I'm editing this to say that I've confused you with Quaz -- when I write things like "your child would likely be in a group alone" or when I call your child "her" I'm thinking of Quaz's child -- I don't know your child's gender or exact skill levels, obviously.