[BUG] Android shows user email addresses even when oCIS is configured to hide them

Problem

Android shows user email addresses even when oCIS is configured to hide them.

This is a privacy / information disclosure issue and a client-server behavior mismatch.

Expected behavior

If oCIS disables email visibility, Android must not render email addresses anywhere in the UI (sharee search, share dialogs, member lists, mentions, etc.).

Actual behavior

Android still displays email addresses although the oCIS setting is disabled.

Engineering scope

Please implement and verify the full propagation path:

1. oCIS config: email-visibility setting is configured in frontend/web config (WEB_OPTION_* / WEB_UI_CONFIG_FILE)
2. Capabilities/API: effective value is exposed to clients (or add a stable capability flag)
3. Android parsing: Android reads/stores the flag
4. UI enforcement: all user/sharee UI rendering respects the flag
5. Tests: regression coverage for both states (show/hide email)

Acceptance criteria

• Android respects the oCIS email-visibility capability/setting
• No email addresses are shown when disabled
• Email display still works when enabled
• Regression tests added
• Capability key / endpoint used is documented

Impact

Privacy / information disclosure (personal email addresses shown despite server-side policy).

Environment

• Server: oCIS
• Client: ownCloud Android
• Type: Bug / Privacy