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/build.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# Build .skill archives from skills/<name>/ into dist/<name>.skill
+# Usage: build.sh [name...]   (no args = all)
+#
+# Uses `zip` if available; otherwise delegates to scripts/build.ps1
+# (so the script works on Linux, macOS, and Windows-with-git-bash without
+# requiring `zip` on Windows).
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+SRC="$ROOT/skills"
+DIST="$ROOT/dist"
+
+if command -v zip >/dev/null 2>&1; then
+  mkdir -p "$DIST"
+  if [ "$#" -eq 0 ]; then
+    mapfile -t names < <(find "$SRC" -mindepth 1 -maxdepth 1 -type d -printf '%f\n' | sort)
+  else
+    names=("$@")
+  fi
+  for name in "${names[@]}"; do
+    src_dir="$SRC/$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: $name (missing SKILL.md)" >&2
+      continue
+    fi
+    out="$DIST/$name.skill"
+    rm -f "$out"
+    ( cd "$SRC" && zip -qr "$out" "$name" )
+    echo "built: dist/$name.skill"
+  done
+elif command -v powershell.exe >/dev/null 2>&1; then
+  # Windows fallback: delegate to build.ps1 (proper ZIP via .NET API).
+  ps1="$SCRIPT_DIR/build.ps1"
+  if [ "$#" -eq 0 ]; then
+    powershell.exe -NoProfile -ExecutionPolicy Bypass -File "$(cygpath -w "$ps1" 2>/dev/null || echo "$ps1")"
+  else
+    # Build a comma-separated PS argument list.
+    joined=$(printf ",'%s'" "$@")
+    joined="${joined:1}"
+    powershell.exe -NoProfile -ExecutionPolicy Bypass -File "$(cygpath -w "$ps1" 2>/dev/null || echo "$ps1")" -Names "$joined"
+  fi
+else
+  echo "error: need either 'zip' (Linux/macOS) or PowerShell (Windows) to build .skill archives" >&2
+  exit 1
+fi