v2026.5.11171008

Changes:

• #800: Update release agent with explicit dev bump PR steps
• #799: Bump version to 2026.5.0-dev
• #798: Add manual validation stage to stable release pipeline
• #797: Switch stable pipeline trigger to release branches only
• #795: Narrow stable pipeline tag trigger to v* pattern
• #794: Bump version to 2026.4.0
• #793: Add release agent instructions

This list of changes was auto generated.