test: add index cases

doc: add index to releases directory

test: add test case for max/min function

enh(query): enable the limit clause to be push down

test: finish testcase for TD-19847

fix: rm debug log

test: restore case

refactor(sync): check pSyncTimer NULL

test:fix case about revote ,this case need modify later

fix: continue to fetch next row if deleted

fix(query): uniform the format of result between 2.6 and 3.0

fix:defects in coverity

test(wal): rollback multiple file

Co-authored-by: tomchon <haoran920c@163.com>

test: add test case about vnode for cluster 

fix(query): comment out unused functions for code coverage

fix(coverage): remove the function about skiplist callback

feat(stream):add ci

test: add robustness testcase of wal index files

fix: remove tarray's batch remove test

fix: fix scheduler status error

test: finish testcases for TD-19851

fix: push down limit