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, 7 insertions, 0 deletions

diff --git a/internal/models/types.go b/internal/models/types.go
index 41ba162..1decd93 100644
--- a/internal/models/types.go
+++ b/internal/models/types.go
@@ -29,6 +29,13 @@ type Task struct {
 	RecurrenceSeriesID     string     `json:"recurrence_series_id,omitempty"`
 	NextOccurrenceOverride *time.Time `json:"next_occurrence_override,omitempty"`
 
+	// CommittedDate is "I chose to do this on this day," deliberately distinct
+	// from DueDate, which after migration 031 means only an externally-imposed
+	// deadline. The day's list is a pull of committed work plus real deadlines,
+	// rather than a push of everything unblocked -- which is what makes ending a
+	// day at zero possible.
+	CommittedDate *time.Time `json:"committed_date,omitempty"`
+
 	// Chain membership (doot-native tasks only). ChainID != "" is the
 	// indicator that a task belongs to a linear task chain.
 	ChainID       string `json:"chain_id,omitempty"`