Throw ObjectNotFoundException from FindRequired; add run-console wrappers

- DbBase.FindRequired / Client.FindByNameRequired now throw the
  domain-specific ObjectNotFoundException (NHibernate lineage; Rails
  equivalent: ActiveRecord::RecordNotFound) on a lookup miss; the
  no-context case stays InvalidOperationException (configuration error)
- Console demo catches the new type; tests (18)/(21) assert it,
  (19)/(23) keep InvalidOperationException with rationale comments
- scripts/run-console.sh delegates to dotnet.sh; run-console.ps1 is
  the Windows/PowerShell counterpart (mise-first, repo-root cd)

Yak: objectnotfoundexception-run-console-wrappers-3p8b

scripts/run-console.ps1

@@ -0,0 +1,39 @@
+# Run the Before.Console demo app (src/Before.Console/Program.cs) on Windows.
+#
+# Windows counterpart of scripts/run-console.sh:
+# - runs from the repo root, like the other scripts
+# - prefers mise (see mise.toml) and falls back to a dotnet on PATH
+#
+# Troubleshooting: if dotnet fails with "The user's home directory could not
+# be determined" (some sandboxed shells), set DOTNET_CLI_HOME first:
+#   PS> $env:DOTNET_CLI_HOME = "$PWD\.dotnet-cli"
+#
+# Usage (from anywhere):
+#   PS> .\scripts\run-console.ps1             # no args
+#   PS> .\scripts\run-console.ps1 --verbose   # args go to the program
+# The script inserts the `--` separator for dotnet run itself.
+#
+# If script execution is blocked by policy:
+#   PS> powershell -ExecutionPolicy Bypass -File .\scripts\run-console.ps1
+$ErrorActionPreference = 'Stop'
+
+$repoRoot = Split-Path -Parent $PSScriptRoot
+Push-Location $repoRoot
+try {
+    $dotnetArgs = @('run', '--project', 'src/Before.Console')
+    if ($args.Count -gt 0) {
+        $dotnetArgs += '--'
+        $dotnetArgs += $args
+    }
+
+    if (Get-Command mise -ErrorAction SilentlyContinue) {
+        mise exec -- dotnet @dotnetArgs
+    }
+    else {
+        dotnet @dotnetArgs
+    }
+    exit $LASTEXITCODE
+}
+finally {
+    Pop-Location
+}

scripts/run-console.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# Run the Before.Console demo app (src/Before.Console/Program.cs).
+# Delegates to scripts/dotnet.sh — see there for why the wrapper exists
+# (mise-installed dotnet, DOTNET_CLI_HOME, run from repo root).
+#
+# Usage: scripts/run-console.sh [app args]
+#   scripts/run-console.sh              # no args
+#   scripts/run-console.sh -- --verbose # args are passed to the program
+set -euo pipefail
+exec "$(cd "$(dirname "$0")" && pwd)/dotnet.sh" run --project src/Before.Console -- "$@"