feat(modules): company-context module surfaces and schema-driven settings

Adds the read-only company "Active Modules" index page (lists every
instance-activated module with a Settings shortcut) and the schema-driven
settings framework (generic BaseSchemaForm.vue renderer + per-company
persistence in CompanySetting). Bundled because they share the same
routes/api.php edit and the index page's Settings button targets the
settings page.

Backend:

- CompanyModulesController::index() returns every Module::enabled = true row
  with a kebab-case slug (via Str::kebab()) and a has_settings flag computed
  from \InvoiceShelf\Modules\Registry::settingsFor(). nwidart stores module
  names in PascalCase ("HelloWorld") but URLs and registry keys use kebab
  ("hello-world") — the controller normalizes so module authors can call
  Registry::registerSettings('hello-world') naturally without thinking
  about the storage format.

- ModuleSettingsController::show(\$slug) returns the registered Schema +
  per-company values from CompanySetting (defaults flow through when nothing
  has been saved yet). update(\$slug) builds Laravel validator rules from
  the Schema's per-field rules arrays — with type-rule fallbacks for
  switch -> boolean, number -> numeric, multiselect -> array — silently
  drops unknown keys, and persists via CompanySetting::setSettings() under
  the module.{slug}.{key} prefix. Activation is instance-global, but
  settings are per-company: two companies on the same instance can
  configure the same activated module differently.

- routes/api.php mounts GET /api/v1/company-modules at the root of the
  company API group and GET/PUT /api/v1/modules/{slug}/settings inside the
  existing modules prefix.

Frontend:

- BaseSchemaForm.vue is the central new component — a generic schema-driven
  form renderer that maps schema fields to BaseInput / BaseTextarea /
  BaseSwitch / BaseMultiselect by type, and builds Vuelidate rules
  dynamically from each field's rules array (supports required, email, url,
  numeric, min:N, max:N). New fields are added by extending the type ->
  component map.

- CompanyModulesIndexView.vue fetches /company-modules and renders a card
  grid (with empty/loading states); CompanyModuleCard.vue is the per-row
  component with the Settings button. ModuleSettingsView.vue fetches
  /modules/{slug}/settings, hands {schema, values} to BaseSchemaForm, and
  posts back on submit.

- Company-context routes.ts is rebuilt after the previous commit relocated
  the marketplace browser away. It now declares modules.index +
  modules.settings, both gated by manage-module ability.

- New api/services/{companyModules,moduleSettings}.service.ts thin clients.

- lang/en.json adds modules.index.{description,empty_title,empty_description},
  modules.settings.{title,open,saved,not_found,none}, and
  modules.sidebar.section_title. The sidebar key is added here even though
  the dynamic sidebar rendering lands in the next commit — keeping all i18n
  additions in one file edit avoids hunk-splitting lang/en.json.

lang/en.json

@@ -773,7 +773,22 @@
     "no_modules_installed": "No Modules Installed Yet!",
     "disable_warning": "All the settings for this particular will be reverted.",
     "what_you_get": "What you get",
-    "sign_up_and_get_token": "Sign up & Get Token"
+    "sign_up_and_get_token": "Sign up & Get Token",
+    "index": {
+      "description": "Modules activated by your administrator on this instance. Each company configures its own settings independently.",
+      "empty_title": "No active modules",
+      "empty_description": "Your administrator hasn't activated any modules on this instance yet. Once they do, modules will appear here with a settings shortcut."
+    },
+    "settings": {
+      "title": "Module Settings",
+      "open": "Settings",
+      "saved": "Module settings saved successfully.",
+      "not_found": "This module has not registered a settings schema.",
+      "none": "No settings"
+    },
+    "sidebar": {
+      "section_title": "Modules"
+    }
   },
   "members": {
     "title": "Members",