docs: index.md architecture tree describes transient/ as 'scan/loop strategies' but only lax.while_loop is used

[github-actions]

File: docs/index.md

Location: Line 98, architecture tree

Current text:

│   ├── transient/       # Transient analysis (scan/loop strategies)

Problem:
The comment says "scan/loop strategies", implying lax.scan is one of the strategies available. However, the vajax/analysis/transient/ directory only contains full_mna.py which uses lax.while_loop (adaptive timestep requires early exit, which lax.scan cannot do).

The transient directory contains:

• full_mna.py — uses lax.while_loop for the outer time loop and inner NR loop
• adaptive.py — adaptive timestep configuration
• predictor.py — voltage predictor
• base.py — base class

There is no lax.scan-based transient implementation. The (scan/loop strategies) comment is misleading and contradicts the actual code.

Fix: Change the comment to reflect what's actually there, e.g.:

│   ├── transient/       # Transient analysis (lax.while_loop, adaptive timestep)

Related to issue #99 (same incorrect lax.scan claim in architecture_overview.md).