Fix DENSIFY formula syntax error - missing closing parentheses

[Jython1415]

Summary

Fixes a syntax error in the DENSIFY formula that caused "Formula parse error; check formula syntax" in Google Sheets.

Problem

The FILTER/BYROW/LAMBDA expressions in strict mode were missing closing parentheses:

• Row filtering (line 42): Had 2 closing parens, needed 3
• Column filtering (line 55): Had 2 closing parens, needed 3

Each expression opens 3 functions (FILTER, BYROW, LAMBDA) but was only closing 2 of them.

Changes

Added the missing closing parenthesis in both locations:

Before:

FILTER(range, BYROW(range, LAMBDA(r, SUMPRODUCT(...) >= threshold)),

After:

FILTER(range, BYROW(range, LAMBDA(r, SUMPRODUCT(...) >= threshold))),

Testing

• ✅ Linter passes: uv run scripts/lint_formulas.py
• ✅ README generation passes: uv run scripts/generate_readme.py
• ✅ Parentheses balanced: All lines now show correct depth

Impact

• Fixes DENSIFY formula (all modes)
• Fixes DENSIFYROWS (which calls DENSIFY)
• Both formulas should now work correctly in Google Sheets