feat: migrate 12 personal skills + add build/install scripts

- skills/: editable sources for all 12 personal skills (caveman family,
  find-skills, project-bootstrap, task-status-wiki, using-context7,
  using-markitdown, wiki-maintainer, compress)
- dist/: built .skill archives, committed (cross-machine deploy without
  needing zip on the target)
- scripts/build.sh + build.ps1: zip skills/<name>/ into dist/<name>.skill;
  Windows fallback uses .NET ZipArchive (PS 5.1 Compress-Archive writes
  backslashes that break extraction on *nix)
- scripts/install.sh: copy skills/<name>/ into ~/.claude/skills/<name>/
  ($CLAUDE_SKILLS_DIR overrides target)
- .wiki/source/repo-layout.md, build-notes.md: design + gotchas
- .gitignore: keep dist/ tracked

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/install.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Install skills/<name>/ into ~/.claude/skills/<name>/ (or $CLAUDE_SKILLS_DIR)
+# Usage: install.sh [name...]   (no args = all)
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+SRC="$ROOT/skills"
+TARGET="${CLAUDE_SKILLS_DIR:-$HOME/.claude/skills}"
+
+if [ "$#" -eq 0 ]; then
+  mapfile -t names < <(find "$SRC" -mindepth 1 -maxdepth 1 -type d -printf '%f\n' | sort)
+else
+  names=("$@")
+fi
+
+mkdir -p "$TARGET"
+
+for name in "${names[@]}"; do
+  src_dir="$SRC/$name"
+  dst_dir="$TARGET/$name"
+  if [ ! -d "$src_dir" ]; then
+    echo "skip: $name (not found in skills/)" >&2
+    continue
+  fi
+  if [ ! -f "$src_dir/SKILL.md" ]; then
+    echo "skip: $name (missing SKILL.md)" >&2
+    continue
+  fi
+  rm -rf "$dst_dir"
+  cp -R "$src_dir" "$dst_dir"
+  echo "installed: $name → $dst_dir"
+done