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/core/bmad-index-docs/SKILL.md

@@ -0,0 +1,66 @@
+---
+name: bmad-index-docs
+description: 'Generates or updates an index.md to reference all docs in the folder. Use if user requests to create or update an index of all files in a specific folder'
+---
+
+# Index Docs
+
+**Goal:** Generate or update an index.md to reference all docs in a target folder.
+
+
+## EXECUTION
+
+### Step 1: Scan Directory
+
+- List all files and subdirectories in the target location
+
+### Step 2: Group Content
+
+- Organize files by type, purpose, or subdirectory
+
+### Step 3: Generate Descriptions
+
+- Read each file to understand its actual purpose and create brief (3-10 word) descriptions based on the content, not just the filename
+
+### Step 4: Create/Update Index
+
+- Write or update index.md with organized file listings
+
+
+## OUTPUT FORMAT
+
+```markdown
+# Directory Index
+
+## Files
+
+- **[filename.ext](./filename.ext)** - Brief description
+- **[another-file.ext](./another-file.ext)** - Brief description
+
+## Subdirectories
+
+### subfolder/
+
+- **[file1.ext](./subfolder/file1.ext)** - Brief description
+- **[file2.ext](./subfolder/file2.ext)** - Brief description
+
+### another-folder/
+
+- **[file3.ext](./another-folder/file3.ext)** - Brief description
+```
+
+
+## HALT CONDITIONS
+
+- HALT if target directory does not exist or is inaccessible
+- HALT if user does not have write permissions to create index.md
+
+
+## VALIDATION
+
+- Use relative paths starting with ./
+- Group similar files together
+- Read file contents to generate accurate descriptions - don't guess from filenames
+- Keep descriptions concise but informative (3-10 words)
+- Sort alphabetically within groups
+- Skip hidden files (starting with .) unless specified