Redesign: clear active nav state, Shipping labels + Receipts get free-text/raw print, shared label repository

- Home page is now just the print server overview, no more unrelated
  network links (3D printers, Cockpit) left over from when this was a
  general landing page.
- Navbar shows which section is active; Brother's per-printer buttons
  now live under a dedicated Brother nav item instead of always-visible.
- Shipping labels: paste raw ZPL directly (no need to save to a file
  first), with a Labelary preview link alongside it.
- Receipts: paste already-formatted ESC/POS text directly, printed as-is.
- Both can save what they just printed into a shared label repository
  (lib/label_repository.rb, one JSON file per label under data/labels/)
  for reprinting later -- saving happens independently of whether the
  print itself succeeds, so a failed/offline printer doesn't lose the
  content.

app.rb

@@ -4,6 +4,7 @@ require "sinatra/reloader"
 require 'tmpdir'
 require 'net/http'
 require_relative 'lib/receipt_builder'
+require_relative 'lib/label_repository'
 
 set :protection, :except => :frame_options
 set :environment, :production
@@ -24,6 +25,8 @@ TEST_LABEL_PDF = File.join(File.dirname(__FILE__), 'test-label.pdf')
 
 PRINTER_DEVICE_EPSON = '/dev/usb/lp_epson' # see /etc/udev/rules.d/99-epson.rules
 
+LABEL_REPO = LabelRepository.new(File.join(File.dirname(__FILE__), 'data', 'labels'))
+
 BROTHER_PRINTERS = {
   'ql560'  => { port: 8560, label: 'Brother QL-560' },
   'ql700'  => { port: 8700, label: 'Brother QL-700' },
@@ -104,6 +107,16 @@ helpers do
     receipt.print!(PRINTER_DEVICE_EPSON)
   end
 
+  # Prints already-formatted ESC/POS text as-is (just the reset + code page
+  # prefix and a trailing cut) -- for content prepared elsewhere or reprinted
+  # from the label repository, unlike print_receipt's title/body template.
+  def print_raw_escpos(content)
+    receipt = ReceiptBuilder.new
+    receipt.align(:left).text(content)
+    receipt.feed(3).cut
+    receipt.print!(PRINTER_DEVICE_EPSON)
+  end
+
   # Transparently reverse-proxies the current request to one of the
   # brother_ql_web instances, so all three printers (web UI and API alike)
   # are reachable through this single sinatra port instead of their own
@@ -153,9 +166,26 @@ get '/' do
 end
 
 get '/upload' do
+  @labels = LABEL_REPO.all(type: 'zpl')
   erb :upload
 end
 
+post '/shipping/zpl' do
+  zpl = params[:zpl].to_s
+  if zpl.strip.empty?
+    flash 'ZPL text is empty', 'warning'
+  else
+    LABEL_REPO.save(name: params[:save_as], type: 'zpl', content: zpl) unless params[:save_as].to_s.empty?
+    begin
+      print_to_datamax(zpl)
+      flash 'ZPL sent to printer', 'success'
+    rescue => e
+      flash "ZPL print failed (#{e.message})", 'danger'
+    end
+  end
+  redirect '/upload'
+end
+
 post '/upload' do
     if params[:file]
 
@@ -204,6 +234,7 @@ post '/test-print' do
 end
 
 get '/epson' do
+  @labels = LABEL_REPO.all(type: 'escpos')
   erb :epson
 end
 
@@ -217,6 +248,49 @@ post '/epson/print' do
   redirect '/epson'
 end
 
+post '/epson/raw' do
+  content = params[:content].to_s
+  if content.strip.empty?
+    flash 'Receipt text is empty', 'warning'
+  else
+    LABEL_REPO.save(name: params[:save_as], type: 'escpos', content: content) unless params[:save_as].to_s.empty?
+    begin
+      print_raw_escpos(content)
+      flash 'Sent to Epson printer', 'success'
+    rescue => e
+      flash "Epson print failed (#{e.message})", 'danger'
+    end
+  end
+  redirect '/epson'
+end
+
+post '/labels/:id/print' do
+  label = LABEL_REPO.find(params[:id])
+  halt 404, 'unknown label' unless label
+
+  begin
+    case label['type']
+    when 'zpl'
+      print_to_datamax(label['content'])
+    when 'escpos'
+      print_raw_escpos(label['content'])
+    end
+    flash "Printed '#{label['name']}'", 'success'
+  rescue => e
+    flash "Print failed (#{e.message})", 'danger'
+  end
+  redirect_target = label['type'] == 'zpl' ? '/upload' : '/epson'
+  redirect redirect_target
+end
+
+post '/labels/:id/delete' do
+  label = LABEL_REPO.find(params[:id])
+  redirect_target = label && label['type'] == 'zpl' ? '/upload' : '/epson'
+  LABEL_REPO.delete(params[:id])
+  flash 'Label deleted', 'success'
+  redirect redirect_target
+end
+
 get '/brother' do
   @printers = BROTHER_PRINTERS
   erb :brother_picker