RESOLVED – Workaround Found
Update for anyone following this thread. Intuit actually called me directly and we spent 1.5 hours troubleshooting this together — total time wasted between calls, research, and troubleshooting was 3-4 hours. Posting this so no one else goes through the same.
The credit does NOT calculate at the partnership level on the 1065. Here is exactly what happens in Lacerte:

The 1065 Form 3468 Part V Section A (§48E) does NOT pass any information through to the partner's 1040 — not the facility info, not the Part I questions, not the basis, not the credit amount
The K-1 will show the §48E indicator but nothing flows automatically into the 1040 input screens
Everything must be manually re-entered on each partner's personal return

The workaround — step by step on the 1040:

Go to General Business and Vehicle Credits
Select Investment Credit (Form 3468)
Manually re-enter all Part I facility information (address, dates, construction start, placed in service date)
Manually re-answer all Part I questions (Q7-Q11)
Manually calculate each partner's share of the qualified investment basis per their ownership percentage and enter it
Check Q7 Yes (under 1 MW) — the 30% rate populates automatically here
Credit calculates correctly at 30% of each partner's share of the basis ✓

The 1065 Form 3468 entry should remain in place for documentation and K-1 disclosure purposes. But nothing flows to the 1040 — plan on manual re-entry for every partner.
Hope this saves someone else the 3-4 hours we lost on this.