docs(02-01): add Quick Mode section to help.md

- Add /gsd:quick command documentation
- Place between Execution and Roadmap Management sections
- Document usage, purpose, and output files

.planning/ROADMAP.md

@@ -33,10 +33,10 @@ Plans:
   1. help.md lists `/gsd:quick` with usage and description
   2. README.md includes quick mode section explaining when to use it
   3. GSD-STYLE.md documents quick mode patterns
-**Plans**: TBD
+**Plans:** 1 plan
 
 Plans:
-- [ ] 02-01: TBD
+- [ ] 02-01-PLAN.md — Document /gsd:quick in help.md, README.md, and GSD-STYLE.md
 
 ## Progress
 
@@ -46,4 +46,4 @@ Phases execute in numeric order: 1 -> 2
 | Phase | Plans Complete | Status | Completed |
 |-------|----------------|--------|-----------|
 | 1. Core Command | 2/2 | Complete | 2026-01-19 |
-| 2. Documentation | 0/? | Not started | - |
+| 2. Documentation | 0/1 | Not started | - |

commands/gsd/help.md

@@ -129,6 +129,21 @@ Execute all plans in a phase.
 
 Usage: `/gsd:execute-phase 5`
 
+### Quick Mode
+
+**`/gsd:quick`**
+Execute small, ad-hoc tasks with GSD guarantees but skip optional agents.
+
+Quick mode uses the same system with a shorter path:
+- Spawns planner + executor (skips researcher, checker, verifier)
+- Quick tasks live in `.planning/quick/` separate from planned phases
+- Updates STATE.md tracking (not ROADMAP.md)
+
+Use when you know exactly what to do and the task is small enough to not need research or verification.
+
+Usage: `/gsd:quick`
+Result: Creates `.planning/quick/NNN-slug/PLAN.md`, `.planning/quick/NNN-slug/SUMMARY.md`
+
 ### Roadmap Management
 
 **`/gsd:add-phase <description>`**