docs: add missing changelog entries for commits since v0.50.3

- ai: Vercel AI Gateway routing support (#1051)
- tui: Ctrl+B/Ctrl+F keybindings (#1053), character jump navigation (#1074),
  line boundary navigation (#1050), performance optimizations (#1084)
- coding-agent: set_session_name RPC (#1075), config selector folder names (#1064)
- Cross-package duplication of tui/ai changes to coding-agent
- Add New Features section to coding-agent changelog

packages/ai/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Added
+
+- Added Vercel AI Gateway routing support via `vercelGatewayRouting` option in model config ([#1051](https://github.com/badlogic/pi-mono/pull/1051) by [@ben-vargas](https://github.com/ben-vargas))
+
 ### Fixed
 
 - Updated Antigravity User-Agent from 1.11.5 to 1.15.8 to fix rejected requests ([#1079](https://github.com/badlogic/pi-mono/issues/1079))