sqlite: prevent reentrant statement finalization

[trivikr]

Fixes: #64795

A scalar or aggregate callback can call db.close() while its prepared
statement is executing inside sqlite3_step(). close() then finalizes the
currently executing statement, and execution resumes with an invalid statement,
causing the process to crash. db.deserialize() has the same issue because it
also finalizes existing statements.

This change tracks statement execution depth around sqlite3_step() and
rejects close() and deserialize() with ERR_INVALID_STATE while a statement
is executing.

---

Assisted-by: codex:gpt-5.6-sol

[nodejs-github-bot]

Review requested:

• @nodejs/sqlite

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.16%. Comparing base (bec3d0b) to head (4af37c6).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #64796      +/-   ##
==========================================
+ Coverage   90.14%   90.16%   +0.01%     
==========================================
  Files         746      746              
  Lines      242763   242769       +6     
  Branches    45761    45769       +8     
==========================================
+ Hits       218848   218900      +52     
+ Misses      15402    15351      -51     
- Partials     8513     8518       +5     

Files with missing lines	Coverage Δ
src/node_sqlite.cc	80.92% <100.00%> (+0.04%)	⬆️
src/node_sqlite.h	80.64% <ø> (ø)

... and 36 files with indirect coverage changes

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