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/tea/workflows/testarch/bmad-testarch-automate/workflow-plan.md

@@ -0,0 +1,20 @@
+    # Workflow Plan: testarch-automate
+
+    ## Create Mode (steps-c)
+    - step-01-preflight-and-context.md
+
+- step-02-identify-targets.md
+- step-03-generate-tests.md
+- step-04-validate-and-summarize.md
+
+  ## Validate Mode (steps-v)
+  - step-01-validate.md
+
+  ## Edit Mode (steps-e)
+  - step-01-assess.md
+  - step-02-apply-edit.md
+
+  ## Outputs
+  - {test_artifacts}/automation-summary.md
+
+- Test files under {project-root}/tests