Post-swap hardening after a full BS4-removed-class sweep of the codebase:
- LocationAutocomplete passed `root: 'form-group'` to react-places-autocomplete;
BS5 removed `.form-group` (it gave the bottom margin) -> use `mb-3`.
- Drop the unused `popper.js@1` dependency (react-bootstrap bundles
@popperjs/core@2). No source imports it.
Sweep otherwise clean: no other BS4-only utility/component classes remain in JSX
or SCSS. Full-app build boots clean.
Removes the largest batch of React-19-blocking warnings: the 0.31
components (Grid, FormGroup, ControlLabel, Navbar.Header/Brand, Checkbox,
SafeAnchor) all leaned on legacy context / defaultProps.
29 files converted: Grid->Container, FormGroup/ControlLabel/FormControl/
HelpBlock -> Form.Group/Label/Control/Text, Checkbox -> Form.Check (label
as prop), bsStyle->variant (default->secondary), bsSize->size,
pull-right->float-end. Custom Col.js now re-exports v2's Col; custom
NavItem.js rewritten self-contained (no SafeAnchor/createChainedFunction);
Navigation.js drops react-bootstrap Navbar (raw markup anyway).
CSS stays on Bootstrap 4 (alexwine:bootstrap-4) for now: the BS4->5 jump
is entangled with the jQuery carousel/swipe + navbar-collapse and is
tracked as separate debt in UPGRADE.md. Only .form-label needed a shim
(forms.scss). Browser-verified home carousel+navbar, signup form + terms
checkbox, login form; REST smoke byte-identical.
