Update both docs/configuration.md (user-facing) and
src/resources/extensions/gsd/docs/preferences-reference.md (internal)
with complete coverage of all GSD preferences:
- Add /gsd prefs subcommands table (global, project, status, wizard, setup)
- Document token_profile (budget/balanced/quality) and phases settings
- Document context_pause_threshold field
- Document remote_questions configuration (Slack/Discord)
- Document git.merge_strategy (squash/merge) and git.isolation (worktree/branch)
- Expand post_unit_hooks with missing agent field
- Expand pre_dispatch_hooks with skip_if, unit_type, model fields
and action validation rules
- Add known unit types list for hook before/after arrays
- Add examples for pre-dispatch hooks (modify/skip/replace)
- Add examples for token profile, phases, and remote questions
- Update models to show all 6 phases (research, planning, execution,
execution_simple, completion, subagent)
- Add full example combining all major settings