Feature Request: Clarify UV_HTTP_TIMEOUT format in error message

Problem

The error message for network timeouts is misleading about the expected format:

Failed to download distribution due to network timeout.
Try increasing UV_HTTP_TIMEOUT (current value: 30s).

This suggests users should set values like 120s or 180s, but the actual required format is a plain integer representing seconds.

Current Behavior

Error message shows:

current value: 30s

Users naturally try:

export UV_HTTP_TIMEOUT=120s  # Doesn't work

But must use:

export UV_HTTP_TIMEOUT=120  # Correct - integer seconds

Proposed Solution

Option 1: Clarify the error message (recommended)

Failed to download distribution due to network timeout (30s).
Try increasing UV_HTTP_TIMEOUT to a larger integer value (in seconds).
Example: export UV_HTTP_TIMEOUT=120

Option 2: Support duration suffixes

Accept values with suffixes:

• 120 or 120s (seconds)
• 2m (minutes = 120 seconds)

This follows common CLI conventions (Docker timeout flags, curl --max-time, etc.)

Impact

The misleading format causes user confusion - the error displays 30s which implies the s suffix is part of the format, leading users to try UV_HTTP_TIMEOUT=120s which fails.

Environment

• uv version: (latest as of 2025-11-29)
• OS: Multiple (affects all platforms)