Phase 6b/7b: per-child decoded periods, separate brief blocks, idempotent calendar (AUD-119)

- Parse each child's own "Today" day widget for the timetable (FR-16); drop the
  school-wide week calendar's lesson grid and clean the leaked routine rows.
- Add the editable codes map (FR-17): subjects, rooms, teachers and period
  labels, seeded, an unknown code falls back to the raw code; `school codes` CLI.
- Brief: Finn's block first, then Harry's, four sections always present (FR-9);
  periods decoded into plain English; the undated tail is one counted line (FR-18).
- Calendar: write periods + work due + work overdue + major events, per child,
  on every pass. Identity is the stable per-item key, so a re-run never re-inserts
  (FR-8). morning-brief.sh now runs scan -> calendar push -> notify.
- Day-widget labels are 12-hour: 1-6 read as PM, fixing afternoon periods.

Proven live on .13: image 0.6.2-phase6b7b; both children's briefs decoded and
separate; 35 events in calendar.school; runs 2 and 3 of the scan added nothing.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

cmd/school/parse.go

@@ -150,6 +150,19 @@ func runParse(f parseFlags) error {
 		}
 	}
 
+	// The week calendar is school-wide and carries the eldest child's lesson
+	// grid. Now that this child's own day widget is parsed, drop the leaked
+	// routine periods; the real school events from that page are kept (FR-16).
+	// The day-widget rows themselves are not deleted: the same day's period
+	// upserts onto its own stable reference, so its Home Assistant marker (and
+	// the calendar write's idempotency) is preserved across passes.
+	if hasPage(pages, parse.PageChildProfile) || hasPage(pages, parse.PageLearningTasks) {
+		if _, err := st.DeleteChildRoutineCalendarEvents(ctx, child.ID); err != nil {
+			_, _ = st.RecordScan(ctx, &child.ID, len(pages), len(items), false, err.Error())
+			return err
+		}
+	}
+
 	inserted, updated, err := st.UpsertItems(ctx, child.ID, stored)
 	if err != nil {
 		_, _ = st.RecordScan(ctx, &child.ID, len(pages), len(items), false, err.Error())
@@ -326,6 +339,7 @@ func loadRunPages(rawRoot, child, run string) (string, []parse.Page, error) {
 	type rawPage struct {
 		htmlBytes, jsonBytes []byte
 		url, user            string
+		fetchedAt            time.Time
 	}
 	bySlug := map[string]*rawPage{}
 	var order []string
@@ -353,13 +367,17 @@ func loadRunPages(rawRoot, child, run string) (string, []parse.Page, error) {
 				return "", nil, fmt.Errorf("read %s: %w", name, err)
 			}
 			var meta struct {
-				URL    string `json:"url"`
-				UserID string `json:"userId"`
+				URL       string `json:"url"`
+				UserID    string `json:"userId"`
+				FetchedAt string `json:"fetchedAt"`
 			}
 			_ = json.Unmarshal(raw, &meta)
 			p := get(slug)
 			p.url = strings.TrimSpace(meta.URL)
 			p.user = strings.TrimSpace(meta.UserID)
+			if ts, err := time.Parse(time.RFC3339, strings.TrimSpace(meta.FetchedAt)); err == nil {
+				p.fetchedAt = ts
+			}
 		case strings.HasSuffix(lower, ".json"):
 			if strings.EqualFold(name, "manifest.json") {
 				continue
@@ -387,11 +405,12 @@ func loadRunPages(rawRoot, child, run string) (string, []parse.Page, error) {
 			continue
 		}
 		pages = append(pages, parse.Page{
-			Slug:   slug,
-			URL:    rp.url,
-			HTML:   rp.htmlBytes,
-			JSON:   rp.jsonBytes,
-			UserID: rp.user,
+			Slug:      slug,
+			URL:       rp.url,
+			HTML:      rp.htmlBytes,
+			JSON:      rp.jsonBytes,
+			UserID:    rp.user,
+			FetchedAt: rp.fetchedAt,
 		})
 	}
 	if len(pages) == 0 {