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 90.13%. Comparing base (6a3d80f) to head (c11abfd).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #64796      +/-   ##
==========================================
- Coverage   90.16%   90.13%   -0.04%     
==========================================
  Files         744      744              
  Lines      242518   242524       +6     
  Branches    45705    45693      -12     
==========================================
- Hits       218670   218601      -69     
- Misses      15357    15422      +65     
- Partials     8491     8501      +10     

Files with missing lines	Coverage Δ
src/node_sqlite.cc	80.71% <100.00%> (+0.04%)	⬆️
src/node_sqlite.h	80.64% <ø> (ø)

... and 35 files with indirect coverage changes

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