UI Suggestions for Account Types in Setup Modal + Stats-Based Inactive Handling (#368)

* - Add tests for `Simplefin::AccountTypeMapper` and `AccountSimplefinCreation`
- Implement `Simplefin::AccountTypeMapper` for account type inference with fallback-only logic
- Enhance inactive state handling for `SimplefinItem::Importer`
- Improve subtype selection handling in views with confidence-based inference

* Remove unnecessary `.presence` check for `openai_uri_base` in hostings settings

* Refine zero balance detection logic in `SimplefinItem::Importer` and add regression test for missing balances scenario

* Enhance account type and subtype inference logic with explicit investment subtype mapping, improved regex handling, and institution-based credit card detection

* Refine retirement subtype mapping in `AccountTypeMapper` tests with explicit case-based assertions

* Expand `AccountTypeMapper` investment subtype mapping to include `403b` and `tsp` with updated regex definitions

* Remove unused `retirement_hint?` method in `AccountTypeMapper` to simplify codebase

---------

Co-authored-by: Josh Waldrep <joshua.waldrep5+github@gmail.com>

app/controllers/simplefin_items_controller.rb

@@ -165,6 +165,28 @@ class SimplefinItemsController < ApplicationController
       [ "Other Asset", "OtherAsset" ]
     ]
 
+    # Compute UI-only suggestions (preselect only when high confidence)
+    @inferred_map = {}
+    @simplefin_accounts.each do |sfa|
+      holdings = sfa.raw_holdings_payload.presence || sfa.raw_payload.to_h["holdings"]
+      institution_name = nil
+      begin
+        od = sfa.org_data
+        institution_name = od["name"] if od.is_a?(Hash)
+      rescue
+        institution_name = nil
+      end
+      inf = Simplefin::AccountTypeMapper.infer(
+        name: sfa.name,
+        holdings: holdings,
+        extra: sfa.extra,
+        balance: sfa.current_balance,
+        available_balance: sfa.available_balance,
+        institution: institution_name
+      )
+      @inferred_map[sfa.id] = { type: inf.accountable_type, subtype: inf.subtype, confidence: inf.confidence }
+    end
+
     # Subtype options for each account type
     @subtype_options = {
       "Depository" => {