Checker improvements and fixes

[eumalin]

Available to test in dev: https://dev-3.www.hathitrust.org/print-holdings-checker/

I added more detailed instructions, history, and some improvements and fixes.

#	What	Example	Fix
1	No history of checked files	-	Added a history list, saved to localStorage so it survives a reload
2	Dropzone highlight was inconsistent	dragging a file in	Turned out to be event bubbling from nested elements, not the file type. Fixed by checking relatedTarget instead of counting
3	"COLUMNS" label was confusing	-	Renamed to "Columns Detected"
4	"No Errors" badge should be green	-	Was always grey, now it's green
5	Filename errors didn't say they were about the filename	umich_monographs_Full_122122023.tsv	Prefixed those errors with "Filename:", renamed "Type" to "Holdings Type"
6	Bad extension hid the actual filename problems	umich_..._Copy.txt	.txt/.csv files now get checked fully instead of just rejected
7	Same thing, double extension	umich_spm_full_20230711.tsv.txt	Same fix as 6
8	Encoding + column detection was messy	-	Normalized column matching, encoding errors now show a snippet, reworded the column-count message
9	Column checks skipped when type's unknown	umich Hathi 2023.1-DS.tsv	Now checks for oclc/local_id even without a known type
10	Filename parsing didn't say what was wrong	umich_multi-part_20230531.tsv	Added a type-alias list and a per-part breakdown
11	Type/capitalization issues slipped through	umich_mon_Full_12122023.tsv.tsv	Merged the two parsing paths so type and case always get checked
12	Valid date still flagged, type got missed	umich_mpm_full_20230316 (1).tsv	Same fix as 11
13	Spec audit (ISSN, local_id length, partial, ocl7)	-	Added ISSN/local_id checks
-	Review follow-up	-	Fixed a column normalization mismatch, merged duplicate filename logic, caught tab only blank rows, replaced a flaky drag counter

[carylwyatt]

Overall, these are some excellent updates! I'm glad Natalie tested it out with some more robust examples of submissions, she caught a lot more things that could go sideways.

Thanks for all your work on this, it's going to be an amazing addition to our toolset!

[carylwyatt]

I'm very curious about the backstory on this history section. I'm assuming Natalie asked for it, can you explain a little about why we're storing this info about the file submissions?

Since localStorage doesn't have an expiration date, can we add a "clear history" button for folks who don't want their history stored? Librarians are generally conscious of privacy concerns, and while this data is only stored in their browser, let's give them a way to opt out.

[carylwyatt]

Nice improvement! It has happened in the past where we get the wrong file type but more-or-less correct data.

[carylwyatt]

I love the addition of this requirements list! 💯