The formatBigIntCurrency function was ignoring scale, decimals, and suffix
parameters when rendering bigint/bigdecimal numeric fields. This caused
currency annotations like `# currency { scale=k decimals=0 suffix=none }`
to be ignored for bigint fields while working correctly for float fields.

Changes:
- Updated formatBigIntCurrency() to parse and apply scale/decimals/suffix
- Added formatBigIntNumber() for number tag support on bigints
- Updated renderBigNumberField() to use the new functions

Note: When scale is specified, bigints are converted to JS numbers which
is lossy for values > 2^53, but this is acceptable since scaled values
are abbreviated and don't need full precision.

Fixes issue where BigQuery INT64/NUMERIC fields showed unscaled values
like $1,234,567,890.00 instead of scaled $1234568.

Signed-off-by: James Swirhun <james@ms2.co>