feat: add biz-date based source collection date mode

[wgzhao]

Motivation / Background

Some data sources (e.g. securities/funds) should not run automatic collection on non-trading days. Existing source scheduling only supports time-of-day and assumes daily collection

What Changed

• Added source-level date policy collectDateMode with enum values: DAILY, WEEKDAY, WEEKEND.
• Added biz-date aware matcher to evaluate whether a source is collectible on current bizDate.
• Updated source scheduler execution guard to skip when source policy does not match current bizDate.
• Updated daily initialization flow to reset/refresh only matched source IDs instead of all sources.
• Applied source-ID filtering to runnable task queries (including inherited source schedule and table override schedule scan path).
• Updated source save/change detection to include enabled and collectDateMode.
• Updated frontend source form and list to configure and display collection date mode.
• Added schema change in scripts/schema.sql to include etl_source.collect_date_mode.
• Added/updated memory.md with this change summary

Design / Implementation Notes

• Workday definition follows current agreement: Monday-Friday on bizDate.
• Manual single-task submit intentionally bypasses collect-date policy (backfill use case), with explicit why-comments added in code.
• Automatic scheduling/filtering remains strict on bizDate policy.

Validation

• mvn -pl backend -DskipTests compile
• npm run type-check (in frontend/)

Risks / Caveats / Follow-ups

• Database migration is required before deployment: add collect_date_mode column to etl_source with default DAILY.
• Frontend full build (npm run build-only) was not executable in current environment due missing vite command; type-check passed.