fix: consistent zero-padding for decimal phase numbers

Decimal phases now use printf "%02d" formatting to match integer phases.
Before: 6.1-01-PLAN.md vs 06-04-PLAN.md (inconsistent)
After: 06.1-01-PLAN.md vs 06-04-PLAN.md (consistent)

Closes #51

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

commands/gsd/insert-phase.md

@@ -104,7 +104,7 @@ Examples:
 - Phase 72 with 72.1 → next is 72.2
 - Phase 72 with 72.1, 72.2 → next is 72.3
 
-Store as: `decimal_phase="${after_phase}.${next_decimal}"`
+Store as: `decimal_phase="$(printf "%02d" $after_phase).${next_decimal}"`
 </step>
 
 <step name="generate_slug">
@@ -115,7 +115,7 @@ slug=$(echo "$description" | tr '[:upper:]' '[:lower:]' | sed 's/[^a-z0-9]/-/g'
 ```
 
 Phase directory name: `{decimal-phase}-{slug}`
-Example: `72.1-fix-critical-auth-bug`
+Example: `06.1-fix-critical-auth-bug` (phase 6 insertion)
 </step>
 
 <step name="create_phase_directory">

get-shit-done/templates/milestone-archive.md

@@ -47,7 +47,7 @@ Plans:
 
 Plans:
 
-- [x] 2.1-01: Patch auth vulnerability
+- [x] 02.1-01: Patch auth vulnerability
 
 **Details:**
 {{PHASE_DETAILS_FROM_ROADMAP}}

get-shit-done/templates/roadmap.md

@@ -63,7 +63,7 @@ Plans:
 **Plans**: 1 plan
 
 Plans:
-- [ ] 2.1-01: [Description]
+- [ ] 02.1-01: [Description]
 
 ### Phase 3: [Name]
 **Goal**: [What this phase delivers]