fix(workflow): enforce 12-char AskUserQuestion header limit (#559)

Fix hardcoded headers exceeding the 12-character validation limit and
add max-length guidance for dynamically generated headers.

Closes #559

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

get-shit-done/references/questioning.md

@@ -79,6 +79,7 @@ Use AskUserQuestion to help users think by presenting concrete options to react
 - Generic categories ("Technical", "Business", "Other")
 - Leading options that presume an answer
 - Too many options (2-4 is ideal)
+- Headers longer than 12 characters (hard limit — validation will reject them)
 
 **Example — vague answer:**
 User says "it should be fast"

get-shit-done/workflows/discovery-phase.md

@@ -216,7 +216,7 @@ After creating DISCOVERY.md, check confidence level.
 If confidence is LOW:
 Use AskUserQuestion:
 
-- header: "Low Confidence"
+- header: "Low Conf."
 - question: "Discovery confidence is LOW: [reason]. How would you like to proceed?"
 - options:
   - "Dig deeper" - Do more research before planning

get-shit-done/workflows/discuss-phase.md

@@ -136,7 +136,7 @@ ls ${phase_dir}/*-CONTEXT.md 2>/dev/null
 
 **If exists:**
 Use AskUserQuestion:
-- header: "Existing context"
+- header: "Context"
 - question: "Phase [X] already has context. What do you want to do?"
 - options:
   - "Update it" — Review and revise existing context
@@ -240,13 +240,13 @@ Ask 4 questions per area before offering to continue or move on. Each answer oft
    ```
 
 2. **Ask 4 questions using AskUserQuestion:**
-   - header: "[Area]"
+   - header: "[Area]" (max 12 chars — abbreviate if needed)
    - question: Specific decision for this area
    - options: 2-3 concrete choices (AskUserQuestion adds "Other" automatically)
    - Include "You decide" as an option when reasonable — captures Claude discretion
 
 3. **After 4 questions, check:**
-   - header: "[Area]"
+   - header: "[Area]" (max 12 chars)
    - question: "More questions about [area], or move to next?"
    - options: "More questions" / "Next area"
 

get-shit-done/workflows/new-milestone.md

@@ -200,7 +200,7 @@ Present features by category:
 
 **If no research:** Gather requirements through conversation. Ask: "What are the main things users need to do with [new features]?" Clarify, probe for related capabilities, group into categories.
 
-**Scope each category** via AskUserQuestion (multiSelect: true):
+**Scope each category** via AskUserQuestion (multiSelect: true, header max 12 chars):
 - "[Feature 1]" — [brief description]
 - "[Feature 2]" — [brief description]
 - "None for this milestone" — Defer entire category

get-shit-done/workflows/new-project.md

@@ -59,7 +59,7 @@ git init
 **If `needs_codebase_map` is true** (from init — existing code detected but no codebase map):
 
 Use AskUserQuestion:
-- header: "Existing Code"
+- header: "Codebase"
 - question: "I detected existing code in this directory. Would you like to map the codebase first?"
 - options:
   - "Map codebase first" — Run /gsd:map-codebase to understand existing architecture (Recommended)
@@ -303,7 +303,7 @@ questions: [
     ]
   },
   {
-    header: "Model Profile",
+    header: "AI Models",
     question: "Which AI models for planning agents?",
     multiSelect: false,
     options: [
@@ -663,7 +663,7 @@ For each capability mentioned:
 
 For each category, use AskUserQuestion:
 
-- header: "[Category name]"
+- header: "[Category]" (max 12 chars)
 - question: "Which [category] features are in v1?"
 - multiSelect: true
 - options: