Add STM32H533 breakout and buck-boost converter boards (#24)

Replace the Controller project with separate STM32H533-Breakout and
TPS631000-Buck-Boost-Converter KiCad projects. Promote MCP9601-Sensor
to a standalone project with updated schematics and footprints.

Author: corybuecker

.claude/skills/git/SKILL.md

@@ -0,0 +1,119 @@
+# Git Skill
+
+## When to use this skill
+Use this skill when asked to:
+- Summarize the difference between a feature branch and the default branch
+- Write a commit message for a branch or set of changes
+- Describe what a branch does, what it changes, or what it's for
+- Review a diff or changelog in plain language
+
+---
+
+## Core Workflow
+
+### 1. Identify the default branch
+```bash
+git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's@^refs/remotes/origin/@@' \
+  || git remote show origin 2>/dev/null | grep 'HEAD branch' | awk '{print $NF}' \
+  || echo "main"
+```
+Fall back to `main`, then `master` if the above fails.
+
+### 2. Identify the current feature branch
+```bash
+git rev-parse --abbrev-ref HEAD
+```
+
+### 3. Get the merge base (branch point)
+```bash
+git merge-base HEAD <default_branch>
+```
+Always diff from the **merge base**, not the tip of the default branch. This isolates only the commits introduced by the feature branch, excluding any upstream changes merged in.
+
+### 4. Collect the diff and log
+```bash
+# Stat summary (files changed, insertions, deletions)
+git diff --stat $(git merge-base HEAD <default_branch>)
+
+# Full diff (use sparingly for large repos — prefer --stat first)
+git diff $(git merge-base HEAD <default_branch>)
+
+# Commit log on this branch only
+git log --oneline $(git merge-base HEAD <default_branch>)..HEAD
+```
+
+---
+
+## Summarizing the Branch
+
+Produce a short, plain-English summary covering:
+
+1. **What changed** — files, modules, or systems affected
+2. **Why it changed** — the purpose or problem being solved (infer from code and commit messages if not stated)
+3. **Scope** — number of commits, files touched, rough size of the change
+
+Keep the summary to 3–6 sentences. Avoid restating the diff line-by-line. Focus on intent and impact, not mechanics.
+
+### Example summary format
+> This branch adds rate-limit handling to the API client. It introduces a retry loop with exponential backoff in `client.py` and updates `config.py` to expose a `MAX_RETRIES` setting. Three commits touch two files. No tests were changed.
+
+---
+
+## Writing a Commit Message
+
+Use the **imperative mood**, present tense, and keep it direct. Do not over-explain.
+
+### Format
+```
+<Short subject line — 50 chars or fewer>
+
+<Optional body — wrap at 72 chars. Explain WHAT and WHY, not HOW.
+   Omit if the subject line is self-sufficient.>
+```
+
+### Rules
+- **Subject line**: imperative mood ("Add", "Fix", "Remove", "Update") — not "Added" or "Adding"
+- **No period** at the end of the subject line
+- **Body** (optional): explain *why* the change was made if it isn't obvious; omit implementation details that are visible in the diff
+- **No fluff**: avoid "This commit...", "As per discussion...", "Various improvements"
+- If the branch has multiple unrelated concerns, note them with bullet points in the body
+
+### Example commit messages
+
+Single-concern branch:
+```
+Add exponential backoff to API client retries
+```
+
+Multi-concern or non-obvious branch:
+```
+Refactor auth middleware to support token refresh
+
+The previous implementation rejected expired tokens immediately.
+This change adds a refresh attempt before returning 401, matching
+the behavior expected by the mobile clients.
+```
+
+---
+
+## Quick Reference Commands
+
+| Goal | Command |
+|---|---|
+| Default branch | `git symbolic-ref refs/remotes/origin/HEAD \| sed 's@.*/@@'` |
+| Current branch | `git rev-parse --abbrev-ref HEAD` |
+| Merge base | `git merge-base HEAD <default>` |
+| Files changed | `git diff --name-only $(git merge-base HEAD <default>)` |
+| Stat summary | `git diff --stat $(git merge-base HEAD <default>)` |
+| Commit log | `git log --oneline $(git merge-base HEAD <default>)..HEAD` |
+| Full diff | `git diff $(git merge-base HEAD <default>)` |
+
+---
+
+## Notes & Edge Cases
+
+- **Detached HEAD**: if `git rev-parse --abbrev-ref HEAD` returns `HEAD`, ask the user which branch they're working on.
+- **Large diffs**: for repos with thousands of changed lines, use `--stat` and `--name-only` first. Only fetch the full diff for files relevant to the summary.
+- **Merge commits on the branch**: use `git log --no-merges` to exclude them from the commit list when writing the message.
+- **Monorepos**: scope the diff to the relevant subdirectory with `git diff <merge-base> -- <path/to/dir>` if the branch touches only one package.
+- **No remote**: if there's no remote, fall back to comparing against `main` or `master` locally.