Add planner scaffold

src/components/CoursePalette.tsx

@@ -0,0 +1,17 @@
+// Reserved pane for the course palette. A later ticket fills this with course
+// tiles (built from the same `courseList`/`courses` data the Explorer uses) that
+// students drag onto term slots — course tiles are consumed once placed, blanket
+// tiles (electives) are reusable. For now it's a labelled placeholder so the
+// two-pane layout contract is locked and the palette ticket only fills the body.
+//
+// Hidden below md to keep narrow screens to the grid alone.
+export default function CoursePalette() {
+  return (
+    <aside className="hidden w-56 shrink-0 flex-col border-r border-gray-200 p-4 md:flex">
+      <h2 className="text-sm font-semibold text-gray-800">Courses</h2>
+      <p className="mt-2 text-xs text-gray-400">
+        Drag-and-drop course palette — coming soon.
+      </p>
+    </aside>
+  );
+}

src/components/Slot.tsx

@@ -0,0 +1,90 @@
+import { useState, type SyntheticEvent } from 'react';
+import { courses } from '@/data/loadCourses';
+import { usePlannerStore } from '@/store/plannerStore';
+import type { PlannerEntry } from '@/types/planner';
+
+interface Props {
+  termId: string;
+  index: number;
+  entry: PlannerEntry | null;
+}
+
+function normalize(raw: string): string {
+  return raw.trim().toUpperCase().replace(/\s+/g, ' ');
+}
+
+// One course slot box. For now it's a typeable text field holding a course code;
+// a later ticket turns it into a drag-and-drop target. The slot's positional
+// identity is (termId, index) — committing writes through the store's setSlot.
+export default function Slot({ termId, index, entry }: Props) {
+  const setSlot = usePlannerStore((s) => s.setSlot);
+
+  const filledCode = entry?.kind === 'course' ? entry.code : '';
+  const [input, setInput] = useState(filledCode);
+  const [error, setError] = useState<string | null>(null);
+
+  // Re-sync the box when the committed code changes underneath us (e.g. a
+  // template load or future drag-drop replaces the slot). Adjusting state during
+  // render — React's recommended alternative to a syncing effect.
+  const [lastFilled, setLastFilled] = useState(filledCode);
+  if (filledCode !== lastFilled) {
+    setLastFilled(filledCode);
+    setInput(filledCode);
+    setError(null);
+  }
+
+  // elective / choose entries aren't typeable yet (separate ticket). Render them
+  // read-only so a future template's placeholder can't be silently overwritten.
+  if (entry !== null && entry.kind !== 'course') {
+    const label =
+      entry.kind === 'elective' ? entry.category : entry.description;
+    return (
+      <div className="flex h-12 items-center rounded border border-dashed border-gray-300 bg-gray-50 px-2 text-xs text-gray-500 italic">
+        {label}
+      </div>
+    );
+  }
+
+  function commit(e: SyntheticEvent) {
+    e.preventDefault();
+    const code = normalize(input);
+
+    if (code === '') {
+      if (filledCode !== '') setSlot(termId, index, null);
+      setError(null);
+      return;
+    }
+
+    if (!courses.has(code)) {
+      setError('Unknown course code');
+      return;
+    }
+
+    setSlot(termId, index, { kind: 'course', code });
+    setInput(code);
+    setError(null);
+  }
+
+  return (
+    <form onSubmit={commit} className="flex h-12 flex-col justify-center">
+      <input
+        type="text"
+        value={input}
+        onChange={(e) => {
+          setInput(e.target.value);
+          setError(null);
+        }}
+        onBlur={commit}
+        placeholder="e.g. COMP 1405"
+        aria-label={`Course slot ${index + 1}`}
+        aria-invalid={error !== null}
+        className={`w-full rounded border px-2 py-1 text-xs ${
+          error !== null ? 'border-red-500' : 'border-gray-300'
+        }`}
+      />
+      {error !== null && (
+        <p className="px-1 text-[10px] text-red-600">{error}</p>
+      )}
+    </form>
+  );
+}

src/components/TermColumn.tsx

@@ -0,0 +1,25 @@
+import type { Term } from '@/store/plannerStore';
+import Slot from './Slot';
+
+interface Props {
+  term: Term;
+}
+
+// One term's column of slot boxes. Renders off `term.slots` (never a global
+// count) so a future "add slot" ticket that grows a single term's array works
+// without touching this component. A later ticket makes this a DnD drop zone.
+export default function TermColumn({ term }: Props) {
+  return (
+    <div className="flex flex-col gap-2">
+      {/*
+        Key on the slot's stable id, not its index: indices shift when a future
+        remove-slot / reorder ticket moves slots, and an index key would reattach
+        a box's local input/error state to the wrong row. setSlot is still
+        index-addressed — the id is for identity, the index for mutation.
+      */}
+      {term.slots.map((slot, index) => (
+        <Slot key={slot.id} termId={term.id} index={index} entry={slot.entry} />
+      ))}
+    </div>
+  );
+}

src/components/TermGrid.tsx

@@ -0,0 +1,73 @@
+import { seasonLabel, type Term } from '@/store/plannerStore';
+import TermColumn from './TermColumn';
+
+interface Props {
+  terms: Term[];
+}
+
+const ORDINALS = ['First', 'Second', 'Third', 'Fourth', 'Fifth', 'Sixth'];
+
+function yearLabel(year: number): string {
+  const ordinal = ORDINALS[year - 1];
+  return ordinal ? `${ordinal} Year` : `Year ${year}`;
+}
+
+// Groups consecutive terms by year, preserving the earliest-first order. Each
+// group drives one year header that spans its terms' columns.
+function groupByYear(terms: Term[]): { year: number; terms: Term[] }[] {
+  const groups: { year: number; terms: Term[] }[] = [];
+  for (const term of terms) {
+    const last = groups[groups.length - 1];
+    if (last && last.year === term.year) last.terms.push(term);
+    else groups.push({ year: term.year, terms: [term] });
+  }
+  return groups;
+}
+
+// Term-by-term grid: a year-header band on top, Fall/Winter sub-headers, then a
+// column of slot boxes per term. Everything is derived from the `terms` array —
+// no hardcoded term/year count. A single CSS grid (one track per term) keeps the
+// year spans and the slot rows aligned across columns.
+//
+// TODO(ticket: planner legend) — a legend for connector-line / category-colour
+// meaning belongs above this band once those features land.
+export default function TermGrid({ terms }: Props) {
+  const yearGroups = groupByYear(terms);
+
+  return (
+    <div className="overflow-x-auto">
+      <div
+        className="grid min-w-full gap-x-3 gap-y-2"
+        style={{
+          gridTemplateColumns: `repeat(${terms.length}, minmax(11rem, 1fr))`,
+        }}
+      >
+        {/* Row 1 — year headers, each spanning its terms' columns. */}
+        {yearGroups.map((group) => (
+          <div
+            key={group.year}
+            className="rounded bg-gray-100 py-1 text-center text-xs font-semibold tracking-wide text-gray-700 uppercase"
+            style={{ gridColumn: `span ${group.terms.length}` }}
+          >
+            {yearLabel(group.year)}
+          </div>
+        ))}
+
+        {/* Row 2 — Fall/Winter (season) sub-headers, one per term. */}
+        {terms.map((term) => (
+          <div
+            key={term.id}
+            className="text-center text-xs font-medium text-gray-500"
+          >
+            {seasonLabel(term.season)}
+          </div>
+        ))}
+
+        {/* Row 3 — one slot column per term. */}
+        {terms.map((term) => (
+          <TermColumn key={term.id} term={term} />
+        ))}
+      </div>
+    </div>
+  );
+}

src/pages/Planner.tsx

@@ -1,65 +1,34 @@
 // TODO (volunteer tickets):
-// - Drag-and-drop courses between terms
-// - Course palette sidebar with draggable course cards
-// - Autocomplete on the course input
-// - Co-op term special rendering (when COOP courses are added)
-// - Configurable program length (not always 8 terms)
-// - Polished violation rendering (cards, line numbers, jump-to)
-// - Plan export/import as JSON
-// - Share plan via URL hash
-// - Reset plan button with confirm dialog
-// - Render elective placeholder entries (with category label, italic, distinct border color)
-// - Render choose-from-set entries (with credit count + description)
-// - "Start from template" dropdown at the top of the planner; loads a ProgramTemplate via the store's loadTemplate action
-// - Template freshness disclaimer banner shown when a template is loaded (uses validFor and lastReviewed fields)
-// - First curated template content: BCS General (separate PR, content not engineering)
-// - Subsequent templates: BCS Honours, BCS SE Stream, BCS AI Stream, BMath Data Science, Cybersecurity minor
-// - In-planner course detail panel (shared component with Explorer)
-// - In-planner prereq highlighting (click a course, highlight its prereqs in earlier terms and unlocks in later terms)
+// - Course palette panel + drag-and-drop course tiles onto slots (see CoursePalette)
+// - Prereq validation: re-add the violation banner (validatePlan + ViolationList
+//   still exist; map each term's slots → compact entries, dropping nulls)
+// - "Start from template" dropdown (store's loadTemplate) + freshness disclaimer
+// - Render elective / choose entry kinds as styled tiles
+// - "Add slot" / drag-overflow to grow a term up to MAX_SLOTS_PER_TERM
+// - Add / remove terms (summer, year 5+); co-op term rendering
+// - Prereq connector lines between slots; in-planner course detail panel
+// - Plan export/import as JSON; share via URL hash; reset-plan button
 
-import { useMemo } from 'react';
-import { usePlannerStore, termLabel } from '@/store/plannerStore';
-import { courses } from '@/data/loadCourses';
-import { validatePlan } from '@/lib/validatePlan';
-import TermCell from '@/components/TermCell';
-import ViolationList from '@/components/ViolationList';
+import { usePlannerStore } from '@/store/plannerStore';
+import CoursePalette from '@/components/CoursePalette';
+import TermGrid from '@/components/TermGrid';
 
 export default function Planner() {
   const terms = usePlannerStore((s) => s.terms);
 
-  const violations = useMemo(
-    () =>
-      validatePlan(
-        terms.map((t) => ({
-          termId: t.id,
-          label: termLabel(t),
-          entries: t.entries,
-        })),
-        courses,
-      ),
-    [terms],
-  );
-
   return (
-    <div className="flex h-full flex-col gap-4 overflow-y-auto p-4">
-      <ViolationList violations={violations} />
+    <div className="flex h-full overflow-hidden">
+      <CoursePalette />
 
-      <p className="rounded bg-yellow-100 px-3 py-2 text-sm text-yellow-800">
-        This tool validates prerequisite ordering only. It does not check
-        whether courses are offered in specific terms. Verify with the
-        registrar.
-      </p>
+      <main className="flex flex-1 flex-col gap-4 overflow-auto p-4">
+        <p className="rounded bg-yellow-100 px-3 py-2 text-sm text-yellow-800">
+          This tool validates prerequisite ordering only. It does not check
+          whether courses are offered in specific terms. Verify with the
+          registrar.
+        </p>
 
-      <div className="grid grid-cols-2 gap-3">
-        {terms.map((term) => (
-          <TermCell
-            key={term.id}
-            termId={term.id}
-            label={termLabel(term)}
-            entries={term.entries}
-          />
-        ))}
-      </div>
+        <TermGrid terms={terms} />
+      </main>
     </div>
   );
 }