Build me a single-file Streamlit app, dashboard.py. Point it at a folder of IDEA
StatiCa .ideaCon files and show how often each plate thickness, weld size, and
bolt size/grade is used across the project — so I can spot odd sizes and
standardize them. Count one row per occurrence (pandas dataframe: file,
connection, category, size_label). Three sections (Plates/Welds/Bolts), each with
a bar chart (sorted from x axis label smallest to largest not from count), 
a count table, and a dropdown to pick a size and see which file + connection use it.

Read how to use idea statica api https://developer.ideastatica.com/llms.txt

Six things I learned the hard way — get these right:
  1. Don't parse .ideaCon (binary). Don't use export_iom_connection_data either —
     it gives data.plates / data.welds / data.bolt_grids but OMITS the bolt
     assembly, so you can't get bolt sizes. Use export_iom(pid, conn_id), which
     returns the full OpenModelContainer as XML, and parse it with
     xml.etree.ElementTree. Plates/welds/bolt grids are under
     OpenModel/Connections/ConnectionData/{Plates/PlateData, Welds/WeldData,
     BoltGrids/BoltGrid}.
  2. Values come back in METRES — multiply thickness/diameter by 1000 for mm.
  3. The typed export_iom wrapper throws "Unsupported content type:
     application/xml" (it only deserializes JSON). Call
     export_iom_without_preload_content(pid, conn_id) and read raw resp.data bytes.
  4. The body is UTF-8 bytes but the XML declaration says encoding="utf-16", so
     ET.fromstring(bytes) throws "encoding specified in XML declaration is
     incorrect". Decode the bytes yourself (utf-8-sig, utf-16 fallback) and strip
     the leading <?xml ...?> declaration before parsing. The root also has a
     default namespace, so strip namespaces (tag.rsplit('}',1)[-1]) or every
     find('OpenModel') returns None.
  5. Bolt size isn't on the grid; BoltGrid/BoltAssembly/Id is just a reference.
     Match that id against the project bolt-assembly library at
     OpenModel/BoltAssembly/BoltAssembly (each has Id, Name like "M30 8.8", and
     Diameter in metres). These ids ARE self-consistent within the one XML
     document — joining them is the whole point of using export_iom.
  6. Build the bolt label yourself: f"M{round(diameter*1000)} {grade}" -> "M30 8.8",
     where diameter is BoltAssembly/Diameter and grade is the trailing token of
     BoltAssembly/Name. Don't trust the raw Name verbatim, it's inconsistent
     between files.

Skip plates where is_negative_object is true. Skip broken files instead of
crashing. 
When done, let me know how to start the app.