Fix N+1 queries in inheritance API#7936

[acwhite211]

Fixes #7875
Contributed by @foozleface
Based on the #7936 PR with additional fixes

The inheritance post-query processing in api.py ran per-row database queries to look up catalog numbers for parent and COG inheritance. On a query returning 500 rows, this produced 500+ individual SELECT statements. This rewrite collects IDs needing lookup, then bulk-prefetches all catalog numbers in 1-2 queries total. Also increases CSV yield_per from 1 to 2000, which was causing row-at-a-time fetching from the database.

Implementation

• Rewrite parent_inheritance_post_query_processing to collect IDs needing catalog number lookup, then bulk-fetch via a single query using select_related and values_list
• Rewrite cog_inheritance_post_query_processing with two bulk-prefetch steps: (1) get parentcog_id for each child CO, (2) get primary member catalog number for each COG
• Change yield_per(1) to yield_per(2000) in CSV and KML export paths in execution.py
• Add N+1 regression tests that verify bulk queries are used

Testing instructions

• Run a query that includes inherited catalog numbers (e.g., query on Components with catalogNumber column) and verify results are correct
• Export the same query to CSV and verify the file is complete and correct
• Run the test suite: python manage.py test specifyweb.backend.inheritance.tests.test_n_plus_one
• Optionally, enable Django query logging and confirm the inheritance processing uses 1-3 queries instead of N+1

[acwhite211]

Still working on getting this PR working...