fix(goals): demote Behind pill to neutral surface + drop em-dashes

Behavioural + RUI audit follow-ups.

The yellow overload finding flagged three concurrent yellow surfaces
on the show page: the "Behind" status pill, the catch-up alert, and
the open-pledge banner(s). Demoting the alert to outline ownership
of the primary CTA addressed one layer, but the pill kept fighting
the alert for hue attention. "Behind" is a state, not a call to
action; the alert owns the action signal.

Switch the pill's classes from `bg-yellow-500/10 text-yellow-700`
to `bg-surface-inset text-yellow-700` (with the same dark-mode
override). Background goes neutral (matches paused/archived chips);
the text keeps the warning hue and the triangle-alert icon stays.
Signal preserved, weight reduced. The yellow alert below now reads
as the primary nudge instead of one of three matching tones.

Also: copy/em-dash sweep across goal surfaces. User-facing strings
that contained em-dashes ("Reaches 70% — $X of $Y", "into your
linked account — Sure will catch it", "You're at 80% — $X of $Y")
read as a stylistic tic; replace with comma/period/period
respectively. Form-stepper review placeholders "—" become "…"
(ellipsis reads as "not yet set" without the typographic weight).
Code comments + log messages also scrubbed for consistency; awkward
sed artifacts (//. its...) restored to readable English.

No locale-key shape changes; pure string-content edits + one
component-style tweak.

app/javascript/controllers/goal_pledge_preview_controller.js

@@ -28,7 +28,7 @@ export default class extends Controller {
   // Helper text reacts to the currently-selected account, not the goal as a
   // whole. A mixed-funding goal (one connected account + one manual) used to
   // paint the "connected" helper even if the user then picked the manual
-  // account from the dropdown — the saved pledge would be `kind: manual_save`
+  // account from the dropdown; the saved pledge would be `kind: manual_save`
   // (correct, per `kind_for_account` in the controller) but the helper read
   // "transfer-style" copy until submission.
   accountChanged() {