- Drop feature flag and v1 routing
The Conversation API v2 client (OpenAI-compatible) has been the default
since kAIChatConversationAPIV2 shipped as ENABLED_BY_DEFAULT. Always route
Leo model engines to the v2 implementation, retire the feature flag, and
de-parameterize the two AI Chat browser tests that toggled it.
- Remove unused v1 implementation
- Drop redundant V2 suffix
History note: the canonical paths were previously occupied by v1 sources
(removed in 2/3). After this rename, \`git log --follow <path>\`,
\`git blame\`, and GitHub's history view follow the rename and surface
the v2 development history. Plain \`git log <path>\` continues to show
v1's history at those paths up to its removal, then the rename arriving
from the V2-suffixed paths.
Jocelyn Liu
e6ea5cd2f2