Make the day's list a pull of committed work, not a push of everything unblocked

due_date had been carrying two incompatible meanings: "this has a real
deadline" (Bills, meds, a signup cutoff) and "this is when I intend to
work on it." Chains leaned entirely on the second -- every step was
stamped due_date = now the moment it unlocked -- so a five-minute call
and a six-month certification both arrived looking overdue, and the only
way to quiet them was to hand-reschedule. The list therefore always
contained work that could not be finished that day, which made ending a
day at zero impossible by construction rather than by effort.

Splits the two apart:
  - due_date keeps only its real meaning: an externally-imposed deadline.
  - committed_date (new, migration 031) means "I chose this for today."

Chain steps no longer get a due date on unlock (CreateChain, advanceChain,
and the delete-promotion path), and are excluded from the undated list so
they don't simply fall through to it instead. They reach the day only by
being committed, via a "+ today" control on the chain card. Bucket-active
items get the same control. BuildTimeline pulls in committed tasks,
deduped against tasks already present for a different reason (committed
and due-today are two reasons for one row, not two rows).

Migration 031 also clears the auto-stamped due dates from open chain
steps; completed steps keep theirs as historical record.

Two supporting changes made while in here:
  - Extracted the native_tasks SELECT list into nativeTaskColumns. It had
    been copy-pasted into nine queries that must each agree exactly with
    scanNativeTasks' field order; adding committed_date meant editing all
    nine correctly or silently breaking whichever was missed.
  - Extracted templateFuncMap() and added TestTemplates_AllParse. New()
    only logs a warning when template parsing fails, so a malformed
    template shipped silently and surfaced as a broken page at runtime.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018AwnALZL6bD4VBtATDVv3B

1 files changed, 67 insertions, 2 deletions

diff --git a/internal/handlers/chains_timeline_test.go b/internal/handlers/chains_timeline_test.go
index e9c8a3a..d4bc369 100644
--- a/internal/handlers/chains_timeline_test.go
+++ b/internal/handlers/chains_timeline_test.go
@@ -5,10 +5,15 @@ import (
 	"testing"
 	"time"
 
+	"task-dashboard/internal/config"
 	"task-dashboard/internal/models"
 )
 
-func TestBuildTimeline_PopulatesChainBadgeForUnlockedTask(t *testing.T) {
+// Chain steps carry no due date and are kept out of the undated list, so they
+// stay off the day's timeline entirely until deliberately committed. This is the
+// whole point of the pull model: the day contains what was chosen plus real
+// deadlines, so finishing at zero is reachable.
+func TestBuildTimeline_UnlockedChainTaskAbsentUntilCommitted(t *testing.T) {
 	s, cleanup := setupTestDB(t)
 	defer cleanup()
 
@@ -28,6 +33,36 @@ func TestBuildTimeline_PopulatesChainBadgeForUnlockedTask(t *testing.T) {
 	if err != nil {
 		t.Fatalf("BuildTimeline: %v", err)
 	}
+	for _, item := range items {
+		if item.ID == tasks[0].ID {
+			t.Error("uncommitted chain step appeared on the timeline; chain work should only arrive by being committed")
+		}
+	}
+}
+
+func TestBuildTimeline_CommittedChainTaskAppearsWithBadge(t *testing.T) {
+	s, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	chain, err := s.CreateChain("Ham Radio Track", []models.ChainTaskInput{
+		{Content: "Study Technician"}, {Content: "Pass exam"}, {Content: "Study General"},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	tasks, err := s.GetChainTasks(chain.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := s.SetTaskCommitted(tasks[0].ID, config.Now()); err != nil {
+		t.Fatal(err)
+	}
+
+	now := time.Now()
+	items, err := BuildTimeline(context.Background(), s, now.Add(-time.Hour), now.Add(24*time.Hour))
+	if err != nil {
+		t.Fatalf("BuildTimeline: %v", err)
+	}
 
 	var found bool
 	for _, item := range items {
@@ -42,6 +77,36 @@ func TestBuildTimeline_PopulatesChainBadgeForUnlockedTask(t *testing.T) {
 		}
 	}
 	if !found {
-		t.Fatal("expected the unlocked chain task (position 0) to appear in the timeline")
+		t.Fatal("expected the committed chain step to appear on the timeline")
+	}
+}
+
+// A task that is both committed and due today must appear once, not twice.
+func TestBuildTimeline_CommittedAndDueTaskNotDuplicated(t *testing.T) {
+	s, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	due := config.Now()
+	if err := s.CreateNativeTask(models.Task{ID: "dual", Content: "Bills", DueDate: &due}); err != nil {
+		t.Fatal(err)
+	}
+	if err := s.SetTaskCommitted("dual", config.Now()); err != nil {
+		t.Fatal(err)
+	}
+
+	now := time.Now()
+	items, err := BuildTimeline(context.Background(), s, now.Add(-24*time.Hour), now.Add(24*time.Hour))
+	if err != nil {
+		t.Fatalf("BuildTimeline: %v", err)
+	}
+
+	var count int
+	for _, item := range items {
+		if item.ID == "dual" {
+			count++
+		}
+	}
+	if count != 1 {
+		t.Errorf("task appeared %d times, want exactly 1 (committed and due are two reasons for the same row)", count)
 	}
 }