Support interval values and enforce login timeout

[skhe]

Changes

• Round-trip DAY TO SECOND intervals as Python datetime.timedelta, including fractions, negative values, nulls, and a 100,000-day negative boundary. Preserve YEAR TO MONTH type metadata and text binding.
• Fix 32-bit overflow when reading or writing large negative intervals; guard the year-month binding buffer.
• Enforce login_timeout through endpoint selection, TCP dial, and handshake. Correct the connection_timeout seconds conversion.
• Pass and read back app_name, including reserved query characters.
• Add real-DM and unresponsive TCP regression tests. Run patched Go-driver tests in CI.

Verification

• Local official DM8 ARM: Python 3.9–3.13 each passed 121 real-DM tests, with two non-DM tests deselected.
• Targeted tests after the application-name escaping change: 55 passed on Python 3.10.
• Go bridge and patched driver tests, workflow checks, actionlint, and release-asset tests passed.

Object/array, BFILE, SSL, UKey, MPP, and read/write separation behavior remain separate work under the broader quality goal.