[Uber EPIC] Align & Update HSCS Expense Logic

### Problem

There's a few locations where HSCS expense logic can be improved e.g. moving token creation fee into gas (requires gas throttle be increased) and documentation

### Solution

Improve HSCS expense logic

- [ ] HTS System Contract Token Creation Fee Overhead
- [ ] Documentation updates - gas fees
- [ ] FeeSchedule alignments

### Alternatives

_No response_

Start by separating the checklist into HTS System Contract Token Creation Fee Overhead, gas-fee documentation, and FeeSchedule alignments. Trace the existing expense logic and related gas-throttle behavior, then review the current gas-fee documentation. Done means the three listed areas are aligned and the required documentation updates are complete.

Written by the indexing model from the issue text.