chore: clean up repo — add .gitignore, README, remove tracked build artifacts and old_source

- Add .gitignore for bin/, obj/, .vs/, old_source/, IDE files
- Remove 1145 tracked files that should never have been committed
- Add README.md with project overview and build instructions
- Trim CLAUDE.md, add .claudeignore, skills, and PreToolUse hook
- old_source/ is recoverable from the initial commit (6e1b929) if needed

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

.claude/skills/ship.md

@@ -0,0 +1,43 @@
+# Ship — commit and push current changes
+
+The user has finished reviewing and iterating on a section of work. Stage, commit, and push to the Gitea remote.
+
+## Steps
+
+1. **Assess changes.** Run these in parallel:
+   - `git status` — see untracked and modified files
+   - `git diff` and `git diff --cached` — see unstaged and staged changes
+   - `git log --oneline -5` — check recent commit style
+
+2. **Stage files.** Add changed and new files by name. Do NOT use `git add -A` or `git add .` — be explicit to avoid accidentally committing secrets, build artifacts, or files in `.gitignore`.
+
+3. **Draft the commit message.** Follow conventional commits (`feat:`, `fix:`, `refactor:`, `docs:`, `chore:`). Keep it concise — one line summary, optional body if the change is complex. End with:
+   ```
+   Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+   ```
+
+4. **Commit.** Use a HEREDOC for the message:
+   ```bash
+   git commit -m "$(cat <<'EOF'
+   type: summary of changes
+
+   Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+   EOF
+   )"
+   ```
+
+5. **Push.** Push to origin:
+   ```bash
+   git push origin main
+   ```
+   If the push is rejected (remote has new commits), run `git pull --rebase origin main` first, then push again.
+
+6. **Confirm.** Show the user the commit hash and a one-line summary of what was pushed.
+
+## Safety rules
+
+- Never force-push (`--force` / `--force-with-lease`) without explicit user approval
+- Never commit files matching `.gitignore` patterns
+- Never commit `.env`, credentials, or secrets — warn the user if any are staged
+- If there are no changes to commit, tell the user and stop
+- If the user provided arguments after `/ship`, use them as the commit message summary instead of drafting one