feat: Add YAML frontmatter to all 57 task READMEs

Phase 1 of task management consolidation (per Gemini consultation).

Added standardized frontmatter with:
- status: open | blocked | complete
- priority: P1 | P2 | P3 | P4
- owner: Michael | Meg | Holly
- created: YYYY-MM-DD

Final counts:
- 39 open tasks
- 17 complete tasks
- 1 blocked task

Metadata extracted from existing inline markdown and audit results.
Ready for Phase 2: 11ty mobile index generation.

Chronicler #69

docs/tasks/server-matrix-node-fix/README.md

@@ -1,3 +1,10 @@
+---
+status: complete
+priority: P2
+owner: Michael
+created: 2026-04-04
+---
+
 # Task: Fix Server Matrix Node Detection
 
 **Task ID:** #91