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/items.go

@@ -5,6 +5,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"strings"
 
 	"gitea.lab.audasmedia.com.au/sam/compass_teams_nhs/internal/config"
 	"gitea.lab.audasmedia.com.au/sam/compass_teams_nhs/internal/store"
@@ -15,31 +16,43 @@ import (
 // stored against the wrong child ("nothing may leak between children").
 func itemsCommand(args []string) {
 	if len(args) == 0 || args[0] != "purge" {
-		fmt.Fprintln(os.Stderr, "usage: school items purge --child NAME [--source compass|teams] [--type message|task|event]")
+		fmt.Fprintln(os.Stderr, "usage: school items purge --child NAME [--source compass|teams] [--type message|task|event] [--source-page SLUG ...]")
 		os.Exit(2)
 	}
 	fs := flag.NewFlagSet("items purge", flag.ContinueOnError)
 	var (
-		child  string
-		source string
-		typ    string
+		child       string
+		source      string
+		typ         string
+		sourcePages multiFlag
 	)
 	fs.StringVar(&child, "child", "", "child name (Harry or Finn)")
 	fs.StringVar(&source, "source", "", "limit to one source")
 	fs.StringVar(&typ, "type", "", "limit to one type")
+	fs.Var(&sourcePages, "source-page", "limit to one stored page slug (repeatable)")
 	_ = fs.Parse(args[1:])
 
 	if child == "" {
 		fmt.Fprintln(os.Stderr, "school items purge: --child is required")
 		os.Exit(2)
 	}
-	if err := runItemsPurge(child, source, typ); err != nil {
+	if err := runItemsPurge(child, source, typ, sourcePages); err != nil {
 		fmt.Fprintln(os.Stderr, "school items:", err)
 		os.Exit(1)
 	}
 }
 
-func runItemsPurge(child, source, typ string) error {
+// multiFlag collects a repeatable string flag.
+type multiFlag []string
+
+func (m *multiFlag) String() string { return strings.Join(*m, ",") }
+
+func (m *multiFlag) Set(v string) error {
+	*m = append(*m, v)
+	return nil
+}
+
+func runItemsPurge(child, source, typ string, sourcePages []string) error {
 	ctx := context.Background()
 
 	cfg, err := config.LoadDB()
@@ -61,10 +74,15 @@ func runItemsPurge(child, source, typ string) error {
 	if c == nil {
 		return fmt.Errorf("unknown child %q", child)
 	}
-	n, err := st.DeleteItems(ctx, c.ID, source, typ)
+	var n int64
+	if len(sourcePages) > 0 {
+		n, err = st.DeleteItemsFromPages(ctx, c.ID, source, typ, sourcePages...)
+	} else {
+		n, err = st.DeleteItems(ctx, c.ID, source, typ)
+	}
 	if err != nil {
 		return err
 	}
-	fmt.Printf("child=%s purged=%d source=%q type=%q\n", c.Name, n, source, typ)
+	fmt.Printf("child=%s purged=%d source=%q type=%q pages=%v\n", c.Name, n, source, typ, sourcePages)
 	return nil
 }