fix(Postgres Node): Special datetime values cause errors

[riascho]

Summary

The Postgres Node uses the pg module to parse the postgres query response. However, this would fail for some special datetime values in postgres, e.g. infinity, and throw an error "Invalid time value".

This PR adds a check to catch these and return them unparsed.

Since the modified parse function is only for TIMESTAMP or TIMESTAMPTZ values, the only other possible edge case would be null, which is returned correctly. The test table covers that.

To Test:

1. Set up Postgres Test Table:

CREATE TABLE IF NOT EXISTS special_dates
(
   ts timestamp with time zone DEFAULT now()
);

INSERT INTO special_dates (ts)
VALUES
    ('infinity'::timestamptz),
    ('-infinity'::timestamptz),
    ('epoch'::timestamptz),
    ('now'::timestamptz),
    ('today'::timestamptz),
    ('tomorrow'::timestamptz),
    ('yesterday'::timestamptz)
    (NULL);

2. Run the Postgres - Execute Query Node with this query:

SELECT * FROM special_dates;

3. All rows should be output and no error.

Related Linear tickets, Github issues, and Community forum posts

• https://linear.app/n8n/issue/NODE-1245/postgres-special-datetime-values-causes-errors
• PostgreSQL node: Invalid time value error if timestamp column contains special datetime values #8912

Review / Merge checklist

• PR title and summary are descriptive. (conventions)
• Docs updated or follow-up ticket created.
• Tests included.
• PR Labeled with release/backport (if the PR is an urgent fix that needs to be backported)