feat(plugin): ship as Claude Code plugin with 150-line cap and sync command

Turns ClaudeForge into an installable Claude Code plugin and adds the
missing pieces for a clean lifecycle: hard line-cap enforcement, modular
chaining via @path imports, a sync/cleanup command, and Explore-agent
delegation for project discovery.

- .claude-plugin/plugin.json: plugin manifest registering both skills,
  both commands, and the guardian agent (installable via /plugin marketplace
  add alirezarezvani/ClaudeForge && /plugin install claudeforge)
- skill/validator.py: MAX_RECOMMENDED_LINES 300 -> 150 (warning at 120)
- skill/template_selector.py: target_lines capped at 150 across all
  team sizes (solo 75 / small 100 / medium 125 / large 150) so any
  single CLAUDE.md fits within the cap; bigger projects spread content
  across modular sub-files
- skill/analyzer.py: length thresholds, quality scoring, and recommendations
  rebased on the 150 cap (was 300/400)
- skill/generator.py: modular root now emits @path imports next to the
  human-readable links; every sub-CLAUDE.md gets a back-link header
  pointing to ../CLAUDE.md (markdown + @import) for bidirectional chaining
- command/sync-claude-md.md: new /sync-claude-md command that inventories
  every CLAUDE.md, prunes stale references, enforces the 150 cap by
  splitting into sub-files, and repairs the root <-> sub chain
- command/enhance-claude-md.md: discovery phase now delegates the deep
  codebase scan to the Explore subagent to keep context lean
- install.sh / install.ps1: each command in command/ installs as its own
  ~/.claude/commands/<name>.md (legacy bundle backed up on upgrade)
- skill/SKILL.md, CLAUDE.md, README.md, CHANGELOG.md: docs updated for
  the plugin install path, sync command, and new line cap

Verified via smoke test: validator constants, template targets, generator
output line counts across 5 presets (all <= 150), context files with
backlinks, @-import chain in modular root, idempotent merge_with_existing,
validator status transitions at the new cap, analyzer quality differential,
and plugin manifest JSON shape with all referenced paths existing on disk.

install.ps1

@@ -178,7 +178,8 @@ Write-Host ""
 Write-Info "Installation will create:"
 Write-Host "  • Skill:    $skillsDir\claudeforge-skill\"
 Write-Host "  • Skill:    $skillsDir\karpathy-guidelines\"
-Write-Host "  • Command:  $commandsDir\enhance-claude-md\"
+Write-Host "  • Command:  $commandsDir\enhance-claude-md.md"
+Write-Host "  • Command:  $commandsDir\sync-claude-md.md"
 Write-Host "  • Agent:    $agentsDir\claude-md-guardian.md"
 Write-Host ""
 
@@ -231,17 +232,29 @@ if (Test-Path $nestedKarpathy) {
 }
 Write-Success "Karpathy guidelines installed → $karpathyPath\"
 
-# Install slash command
-Write-Info "Installing /enhance-claude-md command..."
-$commandPath = "$commandsDir\enhance-claude-md"
-if (Test-Path $commandPath) {
-    Write-Warning "Existing command found. Creating backup..."
+# Install slash commands. Each .md file in command/ becomes its own
+# top-level command file so it registers as /<name>. README.md is skipped.
+Write-Info "Installing slash commands..."
+
+# Migrate legacy bundle directory if present.
+$legacyBundle = "$commandsDir\enhance-claude-md"
+if (Test-Path $legacyBundle) {
+    Write-Warning "Legacy command bundle found. Creating backup..."
     $backupName = "enhance-claude-md.backup.$(Get-Date -Format 'yyyyMMdd_HHmmss')"
-    Move-Item -Path $commandPath -Destination "$commandsDir\$backupName" -Force
+    Move-Item -Path $legacyBundle -Destination "$commandsDir\$backupName" -Force
     Write-Success "Backup created"
 }
-Copy-Item -Path "command" -Destination $commandPath -Recurse -Force
-Write-Success "Command installed → $commandPath\"
+
+Get-ChildItem -Path "command" -Filter "*.md" -File | Where-Object { $_.Name -ne "README.md" } | ForEach-Object {
+    $cmdTarget = Join-Path $commandsDir $_.Name
+    if (Test-Path $cmdTarget) {
+        Write-Warning "Existing $($_.Name) found. Creating backup..."
+        $backupName = "$($_.Name).backup.$(Get-Date -Format 'yyyyMMdd_HHmmss')"
+        Move-Item -Path $cmdTarget -Destination (Join-Path $commandsDir $backupName) -Force
+    }
+    Copy-Item -Path $_.FullName -Destination $cmdTarget -Force
+    Write-Success "Command installed → $cmdTarget"
+}
 
 # Install guardian agent
 Write-Info "Installing claude-md-guardian agent..."
@@ -363,12 +376,14 @@ Write-Host ""
 if ($scope -eq "user-level") {
     Write-Host "  Remove-Item -Recurse -Force ~\.claude\skills\claudeforge-skill"
     Write-Host "  Remove-Item -Recurse -Force ~\.claude\skills\karpathy-guidelines"
-    Write-Host "  Remove-Item -Recurse -Force ~\.claude\commands\enhance-claude-md"
+    Write-Host "  Remove-Item -Force ~\.claude\commands\enhance-claude-md.md"
+    Write-Host "  Remove-Item -Force ~\.claude\commands\sync-claude-md.md"
     Write-Host "  Remove-Item -Force ~\.claude\agents\claude-md-guardian.md"
 } else {
     Write-Host "  Remove-Item -Recurse -Force .\.claude\skills\claudeforge-skill"
     Write-Host "  Remove-Item -Recurse -Force .\.claude\skills\karpathy-guidelines"
-    Write-Host "  Remove-Item -Recurse -Force .\.claude\commands\enhance-claude-md"
+    Write-Host "  Remove-Item -Force .\.claude\commands\enhance-claude-md.md"
+    Write-Host "  Remove-Item -Force .\.claude\commands\sync-claude-md.md"
     Write-Host "  Remove-Item -Force .\.claude\agents\claude-md-guardian.md"
 }
 Write-Host ""