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.ps1

@@ -0,0 +1,71 @@
+# Build .skill archives from skills/<name>/ into dist/<name>.skill
+# Usage: build.ps1 [-Names <name1>,<name2>]   (no args = all)
+#
+# Uses .NET System.IO.Compression.ZipArchive directly to produce
+# spec-compliant ZIPs with forward-slash entry names (Windows PowerShell 5.1's
+# Compress-Archive writes backslashes, which break extraction on Linux/Mac).
+
+[CmdletBinding()]
+param(
+    [string[]]$Names = @()
+)
+
+$ErrorActionPreference = 'Stop'
+
+$root = Split-Path -Parent $PSScriptRoot
+$src  = Join-Path $root 'skills'
+$dist = Join-Path $root 'dist'
+
+if (-not (Test-Path $dist)) { New-Item -Type Directory -Path $dist | Out-Null }
+
+if ($Names.Count -eq 0) {
+    $Names = Get-ChildItem -Path $src -Directory | Sort-Object Name | Select-Object -ExpandProperty Name
+}
+
+Add-Type -AssemblyName System.IO.Compression
+Add-Type -AssemblyName System.IO.Compression.FileSystem
+
+function New-SkillArchive {
+    param(
+        [string]$SkillName,
+        [string]$SourceDir,
+        [string]$OutPath
+    )
+    if (Test-Path $OutPath) { Remove-Item $OutPath -Force }
+
+    $sourceFull = (Resolve-Path $SourceDir).ProviderPath.TrimEnd('\','/')
+    $archive = [System.IO.Compression.ZipFile]::Open(
+        $OutPath,
+        [System.IO.Compression.ZipArchiveMode]::Create
+    )
+    try {
+        $files = Get-ChildItem -Path $sourceFull -Recurse -File
+        foreach ($file in $files) {
+            $rel = $file.FullName.Substring($sourceFull.Length + 1) -replace '\\','/'
+            $entryName = "$SkillName/$rel"
+            [System.IO.Compression.ZipFileExtensions]::CreateEntryFromFile(
+                $archive,
+                $file.FullName,
+                $entryName,
+                [System.IO.Compression.CompressionLevel]::Optimal
+            ) | Out-Null
+        }
+    } finally {
+        $archive.Dispose()
+    }
+}
+
+foreach ($name in $Names) {
+    $srcDir = Join-Path $src $name
+    if (-not (Test-Path $srcDir -PathType Container)) {
+        Write-Warning "skip: $name (not found in skills/)"
+        continue
+    }
+    if (-not (Test-Path (Join-Path $srcDir 'SKILL.md'))) {
+        Write-Warning "skip: $name (missing SKILL.md)"
+        continue
+    }
+    $out = Join-Path $dist "$name.skill"
+    New-SkillArchive -SkillName $name -SourceDir $srcDir -OutPath $out
+    Write-Host "built: dist/$name.skill"
+}