fix: correct WEEK interval literal duration in calciteLiteralToDruidLiteral (#18665)

[waterWang]

Description

Fixes #18665

INTERVAL 1 WEEK in SQL resolves to PT1H (1 hour) instead of P7D (7 days).

SELECT MILLIS_TO_TIMESTAMP(0) + INTERVAL 1 WEEK

Returns 1970-01-01T01:00:00.000Z instead of 1970-01-08T00:00:00.000Z.

Root Cause

Calcite has a known quirk where WEEK interval literals are stored as 1 hour in the INTERVAL_DAY_TIME family. The INTERVAL 1 WEEK literal's RexLiteral.value() returns 3600000 (1 hour in ms) instead of 604800000 (7 days in ms).

Fix

In calciteLiteralToDruidLiteral, detect the WEEK qualifier on the SqlIntervalQualifier and multiply the stored millisecond value by 7 × 24 to convert from the incorrect 1-hour representation to the correct 7-day duration.

Impact

All INTERVAL N WEEK expressions now correctly resolve to N weeks instead of N hours.
The fix applies to all contexts where INTERVAL_DAY_TIME literals are converted to Druid expressions: timestamp arithmetic (+/-), TIMESTAMPDIFF, and other interval-using operations.

Verification

SELECT MILLIS_TO_TIMESTAMP(0) + INTERVAL 1 WEEK
-- Before: 1970-01-01T01:00:00.000Z
-- After:  1970-01-08T00:00:00.000Z