fix(add-block-skill): restore unknown-output stop in Final Validation

Re-add the "if any tool outputs are still unknown, tell the user instead
of guessing block outputs" step that was dropped when Final Validation
step 5 became the BlockMeta template check.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjefwescJoHZ6zcc3C17FR

Author: TheodoreSpeaks

.agents/skills/add-block/SKILL.md

@@ -889,3 +889,4 @@ After creating the block, you MUST validate it against every tool it references:
 3. **Verify block outputs** cover the key fields returned by all tools
 4. **Verify conditions** — each subBlock should only show for the operations that actually use it
 5. **Verify `{Service}BlockMeta` is exported** with at least 7 templates, each having `icon`, `title`, `prompt`, `modules`, `category`, and `tags`
+6. **If any tool outputs are still unknown**, explicitly tell the user instead of guessing block outputs

.claude/commands/add-block.md

@@ -888,3 +888,4 @@ After creating the block, you MUST validate it against every tool it references:
 3. **Verify block outputs** cover the key fields returned by all tools
 4. **Verify conditions** — each subBlock should only show for the operations that actually use it
 5. **Verify `{Service}BlockMeta` is exported** with at least 7 templates, each having `icon`, `title`, `prompt`, `modules`, `category`, and `tags`
+6. **If any tool outputs are still unknown**, explicitly tell the user instead of guessing block outputs

.cursor/commands/add-block.md

@@ -883,3 +883,4 @@ After creating the block, you MUST validate it against every tool it references:
 3. **Verify block outputs** cover the key fields returned by all tools
 4. **Verify conditions** — each subBlock should only show for the operations that actually use it
 5. **Verify `{Service}BlockMeta` is exported** with at least 7 templates, each having `icon`, `title`, `prompt`, `modules`, `category`, and `tags`
+6. **If any tool outputs are still unknown**, explicitly tell the user instead of guessing block outputs