PARTITION KEY support (#122)

* initial pass at PARTITION KEY support.

* 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.sql

@@ -0,0 +1,49 @@
+.load dist/vec0
+.echo on
+.bail on
+
+.mode qbox
+
+create virtual table v using vec0(a float[1]);
+select count(*) from v_chunks;
+insert into v(a) values ('[1.11]');
+select * from v;
+drop table v;
+
+create virtual table v using vec0(
+
+  v_aaa float[1],
+  partk_xxx int partition key,
+  v_bbb float[2],
+  partk_yyy text partition key,
+  chunk_size=32
+);
+
+
+insert into v(rowid, v_aaa, partk_xxx, v_bbb, partk_yyy) values
+  (1, '[.1]', 999, '[.11, .11]', 'alex'),
+  (2, '[.2]', 999, '[.22, .22]', 'alex'),
+  (3, '[.3]', 999, '[.33, .33]', 'brian');
+
+
+select rowid, vec_to_json(v_aaa), partk_xxx, vec_to_json(v_bbb), partk_yyy from v;
+
+select * from v;
+select * from v where rowid = 2;
+update v
+set v_aaa = '[.222]',
+  v_bbb = '[.222, .222]'
+where rowid = 2;
+
+select rowid, vec_to_json(v_aaa), partk_xxx, vec_to_json(v_bbb), partk_yyy from v;
+
+select chunk_id, size, sequence_id, partition00, partition01, (validity), length(rowids) from v_chunks;
+
+--explain query plan
+select *, distance
+from v
+where v_aaa match '[.5]'
+  and partk_xxx = 999
+  and partk_yyy = 'alex'
+  --and partk_xxx != 20
+  and k = 5;