src: throw on a malformed localStorage file

[TrevorBurnham]

Fixes: #65878

src/node_webstorage.cc asserted the SQLite type of every column it read. But the backing file is a user-specified path, and the schema is created with CREATE TABLE IF NOT EXISTS, so a file that already contains tables of those names is adopted as-is and its values may have any type. Five of those assertions are reachable from crafted data, and each aborts the process. A wrong-typed schema_version is the worst case: the assertion is in Storage::Open(), so any access aborts and the application cannot inspect or repair the file first.

With this PR, the open now throws ERR_INVALID_STATE:

$ node --localstorage-file=/tmp/ws.db -e "localStorage.length"
Error: localStorage database is malformed: expected schema_version to be an integer
  code: 'ERR_INVALID_STATE'

That matches what Open() already does for a file written by a newer Node.js.

Storage::GetAll() is the exception. Its only caller is the DOM Storage inspector agent, so there's no JavaScript caller to throw at. It returns std::nullopt instead, and DOMStorageAgent::getDOMStorageItems() reports a protocol error.

Storage::Length() keeps its CHECK. Its query is SELECT count(*), which is always an integer, so it is not reachable through crafted data.

This also drops a redundant second sqlite3_exec() of the init SQL in Open() that clobbered the result of the sqlite3_prepare_v2() five lines above it, so prepare failures went unreported: a nodejs_webstorage_state table with no schema_version column surfaced as bad parameter or other API misuse.

Tests cover the four JavaScript-reachable sites in test-webstorage.js, plus the inspector path in a new test-inspector-dom-storage-malformed.js.

One follow-up I left out of scope: THROW_SQLITE_ERROR uses sqlite3_errstr(code), so the prepare failure above now reports SQL logic error rather than no such column: schema_version. Switching it to sqlite3_errmsg(db) would improve every throw in the file.

[nodejs-github-bot]

Review requested:

• @nodejs/inspector