feat: initial commit — BMAD tooling, Claude memories, firmware scaffold

Adds the complete project foundation:
- BMAD BMM workflow tooling (_bmad/)
- Claude slash commands, skills, and project memories (.claude/)
- ESP32 firmware scaffold (PlatformIO + Waveshare e-ink driver)
- .gitignore excluding _bmad-output/ and .pio/ build artifacts

Planning artifacts (PRD, architecture, epics) are intentionally not
tracked — they live in _bmad-output/ per project convention.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/bmad-workflow-builder/bmad-manifest.json

@@ -0,0 +1,23 @@
+{
+  "module-code": "bmb",
+  "capabilities": [
+    {
+      "name": "build",
+      "menu-code": "BP",
+      "description": "Build, edit, or convert workflows and skills through six-phase conversational discovery. Covers new skills, format conversion, edits, and fixes.",
+      "supports-headless": true,
+      "prompt": "build-process.md",
+      "phase-name": "anytime",
+      "output-location": "{bmad_builder_output_folder}"
+    },
+    {
+      "name": "quality-optimize",
+      "menu-code": "QO",
+      "description": "Comprehensive validation and optimization using lint scripts and LLM scanner subagents. Structure, prompt craft, efficiency, and more.",
+      "supports-headless": true,
+      "prompt": "quality-optimizer.md",
+      "phase-name": "anytime",
+      "output-location": "{bmad_builder_reports}"
+    }
+  ]
+}