- Update go.mod and Dockerfile to Go 1.26 - Apply `go fix ./...` stdlib modernizations across 170+ files - Add `go fix` to post-implementation checklist in CLAUDE.md - Fix go fix misapplied rewrite in loop_history.go
- Fix opacity/font-size zero detection false positives (0.5, 0.8 matched as zero) - Extract scanWebToolResult helper to eliminate DRY violation in agent loop - Move hidden element detection to dedicated web_fetch_hidden.go file - Replace map false-entries with comments for hiddenClasses documentation