refactor: Major v6 epic creation improvements and documentation overhaul

## Key Changes

### 1. Epic Creation Workflow Enhancements
- Added user-value focused epic structure principles (NO technical layer breakdown)
- Implemented multi-mode detection: CONTINUE, REPLACE, or UPDATE existing epics
- Added comprehensive anti-pattern examples showing wrong vs right epic breakdown
- Epics now created AFTER architecture for technically-informed story breakdown
- Added checkpoint protocol for interactive workflow progression

### 2. Removed Deprecated Solutioning Gate Check
- Deleted entire solutioning-gate-check workflow (682 lines)
- Replaced by new implementation-readiness workflow
- Cleaner separation of concerns in solutioning phase

### 3. PRD Template Simplification
- Removed hardcoded "Implementation Planning", "References", and "Next Steps" sections
- PRD now focuses purely on requirements, not workflow orchestration
- Epics/stories created as separate step after architecture

### 4. Documentation Overhaul (15+ docs updated)
- Updated quick-start guide with v6 workflow sequence
- Clarified that epics are created AFTER architecture, not during PRD
- Updated solutioning docs to reflect implementation-readiness pattern
- Improved agents-guide, brownfield-guide, enterprise docs
- Enhanced glossary, FAQ, and workflow reference documentation

### 5. Workflow Path Adjustments
- All 4 paths updated (enterprise/method × brownfield/greenfield)
- Version bumps across BMGD, BMM, and CIS workflow YAMLs
- Minor instruction file updates for consistency

### Files Changed
- 65 files total: 468 insertions, 978 deletions (net reduction of 510 lines)
- 4 files deleted (entire solutioning-gate-check workflow)
- 1 new directory added (implementation-readiness placeholder)

docs/document-sharding-guide.md

@@ -176,10 +176,11 @@ Workflows load entire sharded documents:
 - `product-brief` - Research, brainstorming docs
 - `prd` - Product brief, research
 - `gdd` - Game brief, research
-- `create-ux-design` - PRD, brief, epics
+- `create-ux-design` - PRD, brief, architecture (if available)
 - `tech-spec` - Brief, research
-- `architecture` - PRD, epics, UX design
-- `solutioning-gate-check` - All planning docs
+- `architecture` - PRD, UX design (if available)
+- `create-epics-and-stories` - PRD, architecture
+- `implementation-readiness` - All planning docs
 
 #### Phase 4 (Selective Load)
 
@@ -284,8 +285,8 @@ input_file_patterns:
 
 ```
 Every workflow loads entire 45k token PRD
-Epic-tech-context for Epic 3: 45k tokens
-Create-story for Epic 3: 45k tokens
+Architecture workflow: 45k tokens
+UX design workflow: 45k tokens
 ```
 
 **After Sharding:**
@@ -298,17 +299,18 @@ Destination: docs/prd/
 Created:
   prd/index.md
   prd/overview.md (3k tokens)
-  prd/epic-1-auth.md (3k tokens)
-  prd/epic-2-dashboard.md (3k tokens)
-  prd/epic-3-reports.md (3k tokens)
-  ...15 epic files
+  prd/functional-requirements.md (8k tokens)
+  prd/non-functional-requirements.md (6k tokens)
+  prd/user-personas.md (4k tokens)
+  ...additional FR/NFR sections
 ```
 
 **Result:**
 
 ```
-Epic-tech-context for Epic 3: 3k tokens (93% reduction!)
-Create-story for Epic 3: 3k tokens (93% reduction!)
+Architecture workflow: Can load specific sections needed
+UX design workflow: Can load specific sections needed
+Significant token reduction for large requirement docs!
 ```
 
 ### Example 2: Sharding Epics File