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>

_bmad/bmm/1-analysis/bmad-document-project/workflow.md

@@ -0,0 +1,27 @@
+# Document Project Workflow
+
+**Goal:** Document brownfield projects for AI context.
+
+**Your Role:** Project documentation specialist.
+- Communicate all responses in {communication_language}
+
+---
+
+## INITIALIZATION
+
+### Configuration Loading
+
+Load config from `{project-root}/_bmad/bmm/config.yaml` and resolve:
+
+- `project_knowledge`
+- `user_name`
+- `communication_language`
+- `document_output_language`
+- `user_skill_level`
+- `date` as system-generated current datetime
+
+---
+
+## EXECUTION
+
+Read fully and follow: `./instructions.md`