Migrate Get Location/Weather + required-field validation out of the
template's inline scripts into the bundle: generalize the field lookup so
weather_desc (now a <select>) is found, gate Get Weather until coords exist,
and add idle/loading/success/error states. Build the 'More options' <details>
(native, KTD5) around the advanced trio, auto-open when any has a value.
Add Field Notes CSS: select/number styling, EasyMDE dark theme, disclosure,
button spinner, and server form-message states.
Refs R5, R11, R12, R18, R19, AE3, KTD5.
Add a page-scoped js/src/post-form.js bundle (built ESM + code-splitting
so U4's heic-to becomes a deferred chunk) loaded only by post-form.html.twig
via a new base head_assets block. EasyMDE replaces the bare textarea with a
minimal toolbar (bold/italic/list/link/preview), FA-free via CSS glyphs, and
syncs codemirror.save() on change + capture-phase submit so the inline
required-field validator and payload see the live value.
Refs R7, R15, KTD2, KTD3.
m038