Release v0.31.8

What's Changed

• docs(skills): route agent renames through self-configuration by @sarahwooders in #4135
• fix(permissions): treat trailing && or || as unparseable for allow-rule matching by @amelia-letta in #4131
• feat(skills): add browser-use builtin by @letta-integration[bot] in #4137
• feat(memory): export default constraints policy [LET-11631] by @letta-integration[bot] in #4140
• refactor(agent): make subagent launches background-only by @letta-integration[bot] in #4138
• fix(memory): count MemFS v2 core files in token estimates by @letta-integration[bot] in #4147
• docs(agent): clarify default conversation resumes [LET-11772] by @amysguan in #4149
• fix(subagents): honor model overrides for forks by @letta-integration[bot] in #4154
• fix(app-server): persist completed ChatGPT OAuth [LET-11432] by @overlord-letta in #4048
• test(windows): stabilize PowerShell launcher coverage [LET-11666] by @just-cameron in #4145
• feat(mcp): add unified MCP CLI by @letta-integration[bot] in #4151
• feat(mcp): add agent tool search command by @letta-integration[bot] in #4155
• chore: bump version to 0.31.8 by @github-actions[bot] in #4163

Full Changelog: v0.31.7...v0.31.8