Add session status file creation rule across workflow commands

Updates all workflow commands to create .workflow/session_status.jsonl if it doesn't exist when checking for active sessions. This ensures consistent behavior across:

- gemini-chat.md: Added creation rule and updated workflow pseudocode
- gemini-execute.md: Added session file creation requirement
- gemini-mode.md: Updated session check process
- workflow/action-plan.md: Updated both session check locations
- task/replan.md: Added creation rule to session validation
- task/breakdown.md: Updated session check process
- workflow/brainstorm.md: Added creation rule to session registry query

Also includes cleanup of deprecated command files (context.md, sync.md) and documentation updates for task creation complexity escalation.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.claude/commands/gemini-execute.md

@@ -192,7 +192,7 @@ This template is automatically filled and generated after execution.
 
 -   **Trigger**: Activated by the `--save-session` flag.
 -   **Action**: Saves the complete execution session, including inferred context, Gemini analysis, and implementation results.
--   **Session Check**: Query `.workflow/session_status.jsonl` to identify current active session.
+-   **Session Check**: Query `.workflow/session_status.jsonl` to identify current active session. If the file doesn't exist, create it.
 -   **Location Strategy**: 
     - **IF active session exists**: Save to existing `.workflow/WFS-[topic-slug]/.chat/` directory
     - **IF no active session**: Create new session directory following WFS naming convention