Add dependency management to issue workflows

Updated skills and commands to identify and formally link issue
dependencies using tea CLI:

Skills updated:
- issue-writing: Document deps in description + link with tea CLI
- backlog-grooming: Check for formal dependency links in checklist
- roadmap-planning: Link dependencies after creating issues

Commands updated:
- create-issue: Ask about and link dependencies for new issues
- plan-issues: Create in dependency order, link with tea issues deps add
- groom: Check dependency status, suggest missing links

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

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

skills/issue-writing/SKILL.md

@@ -104,7 +104,19 @@ Use labels to categorize:
 
 ## Dependencies
 
-Reference related issues:
-- "Depends on #N" - Must complete first
-- "Blocks #N" - This blocks another
-- "Related to #N" - Informational link
+Identify and link dependencies when creating issues:
+
+1. **In the description**, document dependencies:
+   ```markdown
+   ## Dependencies
+   - Depends on #12 (must complete first)
+   - Related to #15 (informational)
+   ```
+
+2. **After creating the issue**, formally link blockers using tea CLI:
+   ```bash
+   tea issues deps add <this-issue> <blocker-issue>
+   tea issues deps add 5 3    # Issue #5 is blocked by #3
+   ```
+
+This creates a formal dependency graph that tools can query.