feat(optimizer)!: databricks type annotation for REGEXP_COUNT, REGEXP_EXTRACT_ALL

[fivetran-amrutabhimsenayachit]

Summary

Adds Databricks type inference support for REGEXP_COUNT (INT) and REGEXP_EXTRACT_ALL (ARRAY), and fixture coverage for REGEXP, REGEXP_COUNT, and REGEXP_EXTRACT_ALL.

Tickets

• RD-1229621 (ADD_MONTHS) — already complete via inheritance, no changes
• RD-1229629 (REGEXP) — fixture entries only
• RD-1229630 (REGEXP_COUNT) — new typing + fixture
• RD-1229631 (REGEXP_EXTRACT) — already complete via inheritance, no changes
• RD-1229632 (REGEXP_EXTRACT_ALL) — new typing + fixture

Test plan

• make style — PASS
• make unit — PASS

[github-actions]

SQLGlot Integration Test Results

✅ All tests passed

Comparing:

• this branch (sqlglot:type-inference-batch-1 @ sqlglot d2c8f9a)
• baseline (main @ sqlglot 7a0a9ab)

Overall

main: 192428 total, 153523 passed (pass rate: 79.8%)

sqlglot:type-inference-batch-1: 180234 total, 142378 passed (pass rate: 79.0%)

Transitions:
No change

Dialect pair changes: 0 previous results not found, 3 current results not found

✅ All tests passed