hardening: migrate remaining process/version lookups to prepared helpers

[somethingwithproof]

Problem

plugin_flowview still has direct raw db_fetch_cell() usage for process/version lookups that should use prepared DB helpers for consistency and safer SQL handling.

Proposed change

• migrate selected raw db_fetch_cell() call sites to db_fetch_cell_prepared() in:
  • flowview_devices.php
  • setup.php
• keep runtime behavior unchanged

Tests

• add standalone regression test asserting the targeted files use prepared calls and no longer use targeted raw query strings
• run syntax checks for touched files