Auxiliary column support (#123)

* initial pass at PARTITION KEY support.

* Initial pass, allow auxiliary columns on vec0 virtual tables

* update TODO

* unit tests

* gha this PR branch

* fixup tests

* doc internal

* fix tests, KNN/rowids in

* define SQLITE_INDEX_CONSTRAINT_OFFSET

* whoops

* update tests, syrupy, use uv

* un ignore pyproject.toml

* dot

* tests/

* type error?

* win: .exe, update error name

* try fix macos python, paren around expr?

* win bash?

* dbg :(

* explicit error

* op

* dbg win

* win ./tests/.venv/Scripts/python.exe

* block UPDATEs on partition key values for now

* test this branch

* accidentally removved "partition key type mistmatch" block during merge

* typo ugh

* bruv

* start aux snapshots

* drop aux shadow table on destroy

* enforce column types

* block WHERE constraints on auxiliary columns in KNN queries

* support delete

* support UPDATE on auxiliary columns