docs: fix agent frontmatter fields and model values across Weeks 5-7

fix: convert commands and skills to proper YAML frontmatter and directory structure

docs: add positional arg clarification and session restart note to Week 5

docs: fix Week 5 command format and PM track sandbox path

docs: standardize intro metadata to bulleted lists across all weeks

docs: standardize sandbox setup commands across all track files

docs: fix sandbox setup commands to copy contents, not directory

docs: move coverage target rationale from troubleshooting to coverage guide

docs: fix Week 3 plan mode prompt formatting to remove bash syntax

docs: fix Week 3 plan mode exercise to use actual bug-hunter project

docs: fix skill argument indexing to 0-based per official docs

docs: fix Weeks 1-2, 9 accuracy, remove phantom office hours, add PRD glossary

docs: redesign Week 8 for 2-hour shared session + role-specific tracks

docs: fix Week 7 accuracy, expand runbook, correct plugin documentation

docs: fix Week 6 accuracy, expand runbook, add cross-platform hook examples