dashboard: fold schedule creation into the table view (closes #564)

The N3W SCH3DUL3 vertical form is gone. The schedules table now
carries an always-visible inline create row at the bottom — fill the
cells, click ＋ to POST /api/schedules, the new schedule appears
above on the next refresh.

Per-column inputs match the display semantics:
- `next` → `<input type="datetime-local">` (defaults to now+5min)
- `every` → 4 mini d/h/m/s number inputs (blank/all-zero = one-shot)
- `body` → `<textarea rows=1>` expanding to 4em on focus-within
  so multi-line prompts still fit (closes mara's "prompt may still be
  multi-line" requirement)
- per-agent columns → checkbox (whole cell clickable via padded label)
- actions → ＋ submit + ⌫ reset (clears the carry without POSTing)

`newScheduleCarry` module-scope object survives the paintAtomic
re-render so mid-typed values stick across schedule-list refreshes
(same pattern as `scheduleEditCarry` from #474).

H2 collapses from "N3W SCH3DUL3" + "QU3U3D SCH3DUL3S" down to a
single "SCH3DUL3S" since the section now does both. Empty-state
branch on `renderSchedulesList` is gone — the table always renders
because the create row is always there.

`#schedule-new-section` div + `renderScheduleNewForm` /
`readScheduleFormCarry` / `submitNewSchedule` and the
`.schedule-new-form` CSS selector all removed. The edit-form path
(#474 `renderScheduleEditForm` colspan'd row on `✎` toggle) is
unchanged — "edit mode is inline in the table" already shipped
there, this PR just adds the same mental model for create.

Validations match the old form: empty targets / empty body /
invalid datetime / non-integer interval each surface an `alert()`.
The ＋ button shows a spinner while the POST is in flight, then
clears the carry + triggers `refreshSchedules()`.

frontend/packages/dashboard/src/dashboard.css

@@ -1693,7 +1693,6 @@ body.flow-shell .tabbar .tab.active.tab-link {
    Cards show: id + source + due-in + cancel-all in the header,
    the prompt body, then a targets table with per-row cancel. */
 
-.schedule-new-form,
 .schedule-edit-form {
   display: flex;
   flex-direction: column;
@@ -1924,6 +1923,109 @@ body.flow-shell .tabbar .tab.active.tab-link {
   padding: 0.1em 0.45em;
 }
 
+/* #564 — inline create row at the bottom of the schedules table.
+   Cells host inputs directly so the operator can fill + click ＋ to
+   queue a new schedule without leaving the table view. Slightly
+   different background tone so it reads as "this isn't a schedule
+   yet, it's the create form". */
+.schedules-table-create-row td {
+  background: rgba(38, 32, 60, 0.25);
+  border-top: 2px solid var(--border);
+  vertical-align: top;
+  padding: 0.4em 0.5em;
+}
+.schedules-table-create-cell {
+  padding: 0.35em 0.4em;
+}
+.schedules-table-inline-input,
+.schedules-table-inline-textarea,
+.schedules-table-inline-num {
+  background: var(--bg);
+  border: 1px solid var(--border);
+  color: var(--fg);
+  font-family: ui-monospace, 'JetBrains Mono', monospace;
+  font-size: 0.85em;
+  padding: 0.2em 0.4em;
+  border-radius: 2px;
+}
+.schedules-table-inline-input:focus,
+.schedules-table-inline-textarea:focus,
+.schedules-table-inline-num:focus {
+  border-color: var(--purple);
+  outline: none;
+}
+.schedules-table-inline-textarea {
+  display: block;
+  width: 100%;
+  min-height: 1.6em;
+  resize: vertical;
+  /* Single-line by default; bumps to 4em on focus so a multi-line
+     prompt has room without the row taking permanent vertical space.
+     :focus-within so resizing-up sticks while focus stays in the row. */
+}
+.schedules-table-create-body:focus-within .schedules-table-inline-textarea {
+  min-height: 4em;
+}
+.schedules-table-inline-desc {
+  display: block;
+  width: 100%;
+  margin-top: 0.25em;
+}
+.schedules-table-inline-datetime {
+  width: 100%;
+  font-size: 0.78em;
+}
+.schedules-table-inline-interval {
+  display: flex;
+  align-items: center;
+  gap: 0.1em;
+  white-space: nowrap;
+}
+.schedules-table-inline-num {
+  width: 2.4em;
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+  /* hide native number spinners — they steal too much width at the
+     2.4em column size and the d/h/m/s buttons aren't useful with no
+     min/max range hint anyway. */
+  -moz-appearance: textfield;
+  appearance: textfield;
+}
+.schedules-table-inline-num::-webkit-outer-spin-button,
+.schedules-table-inline-num::-webkit-inner-spin-button {
+  -webkit-appearance: none;
+  margin: 0;
+}
+.schedules-table-inline-unit {
+  color: var(--muted);
+  font-size: 0.7em;
+  margin-right: 0.15em;
+}
+.schedules-table-inline-check {
+  width: 16px;
+  height: 16px;
+  cursor: pointer;
+  margin: 0;
+}
+.schedules-table-inline-check-lbl {
+  display: inline-flex;
+  cursor: pointer;
+  padding: 0.4em 0.6em;
+  /* Pad out the label so the entire cell is a click target. */
+}
+.schedules-table-create-submit {
+  font-size: 1em;
+  padding: 0.15em 0.55em;
+  color: var(--green);
+  border-color: var(--green);
+}
+.schedules-table-create-reset {
+  font-size: 0.85em;
+  padding: 0.15em 0.45em;
+  color: var(--muted);
+  border-color: var(--border);
+}
+
 /* Selection bar (#443). Sticky-bottom strip that surfaces bulk
    actions when ≥1 agent is selected (click the icon). Visually
    echoes the flow composer's frosted-mauve treatment so the chrome