fix(skills): add missing HALT instructions before user menus

STEP-04 compliance: add explicit HALT directives after menu presentations
in brainstorming (4 locations) and generate-project-context (2 locations)
to prevent LLM from auto-selecting options without waiting for user input.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/bmm/workflows/bmad-generate-project-context/steps/step-01-discover.md

@@ -160,6 +160,8 @@ Ready to create/update your project context. This will help AI agents implement
 
 [C] Continue to context generation"
 
+**HALT — wait for user selection before proceeding.**
+
 ## SUCCESS METRICS:
 
 ✅ Existing project context properly detected and handled

src/bmm/workflows/bmad-generate-project-context/steps/step-02-generate.md

@@ -264,6 +264,8 @@ After each category, show the generated rules and present choices:
 [P] Party Mode - Review from different implementation perspectives
 [C] Continue - Save these rules and move to next category"
 
+**HALT — wait for user selection before proceeding.**
+
 ### 10. Handle Menu Selection
 
 #### If 'A' (Advanced Elicitation):

src/core/skills/bmad-brainstorming/steps/step-01-session-setup.md

@@ -48,6 +48,8 @@ If existing session files are found:
   **[2]** Start a new session
   **[3]** See all existing sessions"
 
+**HALT — wait for user selection before proceeding.**
+
 - If user selects **[1]** (continue): Set `{brainstorming_session_output_file}` to that file path and load `./step-01b-continue.md`
 - If user selects **[2]** (new): Generate new filename with current date/time and proceed to step 3
 - If user selects **[3]** (see all): List all session filenames and ask which to continue or if new
@@ -155,6 +157,8 @@ When user selects approach, append the session overview content directly to `{br
 
 Which approach appeals to you most? (Enter 1-4)"
 
+**HALT — wait for user selection before proceeding.**
+
 ### 4. Handle User Selection and Initial Document Append
 
 #### When user selects approach number:

src/core/skills/bmad-brainstorming/steps/step-03-technique-execution.md

@@ -290,6 +290,8 @@ After final technique element:
 [B] **Take a quick break** - Pause and return with fresh energy
 [C] **Move to organization** - Only when you feel we've thoroughly explored
 
+**HALT — wait for user selection before proceeding.**
+
 **Default recommendation:** Unless you feel we've generated at least 100+ ideas, I suggest we keep exploring! The best insights often come after the obvious ideas are exhausted.
 
 ### 8. Handle Menu Selection

src/core/skills/bmad-brainstorming/steps/step-04-idea-organization.md

@@ -249,6 +249,8 @@ Provide final session wrap-up and forward guidance:
 **Ready to complete your session documentation?**
 [C] Complete - Generate final brainstorming session document
 
+**HALT — wait for user selection before proceeding.**
+
 ### 8. Handle Completion Selection
 
 #### If [C] Complete: