feat(output): configure agent rendering detail

[M09Ic]

Summary

• add configurable Agent output presets and granular YAML controls
• make -v show reasoning plus tool previews and -vv show complete tool results
• preserve compact default output, final-only quiet mode, and predictable Ctrl+O preset cycling
• stabilize the two flaky tests that failed on current master CI

Validation

• focused Go tests pass for config, TUI, CLI, commands, and webagent
• Linux race tests pass for all changed packages
• CI-equivalent Linux race/coverage run passes all packages except the existing external DNSX download timeout in tools/arsenal
• repeated CI regressions pass: Bash proxy test x50, PTY session push test x30
• golangci-lint v2 reports no issues in changed packages (Windows-only existing pidlock conversion remains outside this change)

Release

After this PR is merged and CI is green, republish v0.3.0 from the new master commit.