feat: add UL identifier input support for themes and tenant settings

[harshithRai]

🔧 Changes

This PR adds Deploy CLI support for the UL Identifier Input Refactor & Mobile UX Enhancements initiative, covering two additive Management API surfaces. Both are Early Access and gated behind per-tenant feature flags.

• Bumped auth0 SDK ^6.0.0 → ^6.1.0 to pick up the BrandingThemeIdentifiers and TenantSettingsCountryCodes types, which are wired through the relevant request/response content. No handler logic changes were needed - the fields flow through the existing payload spreads once the types carry them.
• Themes (src/tools/auth0/handlers/themes.ts): added the identifiers object to the theme schema - login_display (separate|unified), otp_autocomplete (boolean), and phone_display (formatting: international|regional, masking: hide_country_code|mask_digits|show_all). Gated by the universal_login_theme_identifiers flag.
• Tenant settings (src/tools/auth0/handlers/tenant.ts): added the nullable country_codes object - list (ISO 3166-1 alpha-2 codes, unique, non-empty) and mode (allow|deny). Set country_codes: null to remove filtering. Gated by the tenant_country_codes_filtering flag.
• Added documentation sections for both surfaces in docs/resource-specific-documentation.md.
  New configuration shapes

Theme identifiers (under a themes entry):

themes:
  - displayName: Default theme
    # ...existing borders, colors, fonts, page_background, widget...
    identifiers:
      login_display: unified          # separate | unified
      otp_autocomplete: true
      phone_display:
        masking: mask_digits          # hide_country_code | mask_digits | show_all
        formatting: international      # international | regional

{
  "displayName": "Default theme",
  "identifiers": {
    "login_display": "unified",
    "otp_autocomplete": true,
    "phone_display": {
      "masking": "mask_digits",
      "formatting": "international"
    }
  }
}

Tenant country_codes (under tenant; set to null to remove filtering):

tenant:
  country_codes:
    list:
      - US
      - GB
      - CA
    mode: allow                       # allow | deny

{
  "country_codes": {
    "list": ["US", "GB", "CA"],
    "mode": "allow"
  }
}

🔬 Testing

• Unit tests added for both surfaces:
  • Themes: identifiers passes through on both create (no existing default theme) and update (existing default theme).
  • Tenant: country_codes object is sent on update, and country_codes: null is preserved to clear filtering.
• Full non-e2e suite: 1332 passing, 1 pending.
• tsc --noEmit, ESLint, and prettier --check all clean.
• Not covered by unit tests: the server-side 400 validation matrix (empty object, list without mode, invalid ISO codes, flag-off rejection) is enforced by the Management API and requires the feature flags enabled on a live tenant; not replicated client-side.

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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