pindexer: dex-explorer: implement low high in summary

[cronokirby]

Describe your changes

Closes #4929.

This was surprisingly simple, we were already doing an aggregate calculation over the window (summing values) so this was just a matter of adding a low and a high.

To test, index against main and check that nothing else has changed besides the addition of two new fields.

Checklist before requesting a review

• I have added guiding text to explain how a reviewer should test these changes.

• If this code contains consensus-breaking changes, I have added the "consensus-breaking" label. Otherwise, I declare my belief that there are not consensus-breaking changes, for the following reason:

  indexing

[conorsch]

To test, index against main and check that nothing else has changed besides the addition of two new fields.

Locally I've run pindexer against a cometbft db based on most recent HEAD of this repo, then again building pindexer from this PR branch, and both completed without errors. Ensuring the diff between the two dbs is as minimal as described is difficult, so I'm going to approve and keep moving: shortly, after landing a few more pindexer fixes, I'll update the db backing the testnet dex-explorer, which gives us more context to analyze the change here.

[conorsch]

N.B. if we moved these large queries to a discrete text file and used include_str on them, then we could lint them with sqlfluff cf. #4759 (comment). I tried on this specific error and the tool reported:

L:  40 | P:   5 |  PRS | Line 40, Position 5: Found unparsable section:
                       | 'COALESCE(MIN(price), 0.0) AS low,\n    CO...'

Not convinced that it's worth moving the queries out of the code just to aid a linter, though. I'd thought that sqlx would catch that syntax error at compile time, but no.

[conorsch]

Approving and merging, along with a batch of other pindexer improvements like #4909 & #4932.