store, ipc: type the routine status, defend the framing with tests (V-410)

Two review threads from PR 4, and the answer to the third.

The routine status was a bare string with its legal set in a comment.
Nothing caught a typo at compile time, nothing enumerated the set for a
test, and a bad value surfaced as a /routines row that neither accepts nor
dismisses. It is a RoutineStatus now, with the three constants, a
RoutineStatuses slice as the single source of truth, and Valid(). Listing
by an unknown status is refused with ErrRoutineStatus instead of answering
"no rows", which is what a correct query says about an empty table. A
round-trip test moves a routine into each state and reads it back, so a
constant that drifts from the inline SQL fails loudly.

The hand-rolled framing stays, and frame.go now says why: ninety lines,
readable with socat, and every standard replacement brings schema
machinery this boundary does not want. What was wrong was inheriting it
untested. frame_test.go covers the paths a real socket produces and the
round-trip test never does — truncated header, truncated body, one byte
per Read, two frames back to back, and a non-JSON body. Empty input is the
only EOF.

The unanswered question in the same file is answered in place: a routine
object stays a local string, not a Nexus ref, because nothing acts on it.
It is the word he used, replayed back to him, compared only against itself
for the UNIQUE key. Canonical refs arrive if a routine ever drives a Hexis
call, which is V-272.

The mood enum has the same shape and is not done here: it is spelled in
the GBNF grammar, three prompts and the parse, so it is its own change.

internal/store/proposed_routines.go

@@ -8,14 +8,37 @@ import (
 	"time"
 )
 
-// The three states a proposal can be in. A proposal starts 'proposed' and
-// moves once, either way, and never moves again.
+// RoutineStatus — the state a proposal is in. A defined type, not a bare
+// string, because the legal set used to live in a comment: nothing caught a
+// typo at compile time, nothing enumerated the set for a test, and a bad value
+// surfaced as a /routines row that neither accepts nor dismisses (Vikunja #46,
+// #410).
+type RoutineStatus string
+
+// The three states a proposal can be in. A proposal starts proposed and moves
+// once, either way, and never moves again.
 const (
-	RoutineProposed  = "proposed"
-	RoutineAccepted  = "accepted"
-	RoutineDismissed = "dismissed"
+	RoutineProposed  RoutineStatus = "proposed"
+	RoutineAccepted  RoutineStatus = "accepted"
+	RoutineDismissed RoutineStatus = "dismissed"
 )
 
+// RoutineStatuses — the legal set, and the single source of truth a test can
+// range over. Adding a state means adding it here.
+var RoutineStatuses = []RoutineStatus{RoutineProposed, RoutineAccepted, RoutineDismissed}
+
+// Valid reports whether s is one of RoutineStatuses.
+func (s RoutineStatus) Valid() bool {
+	for _, v := range RoutineStatuses {
+		if s == v {
+			return true
+		}
+	}
+	return false
+}
+
+func (s RoutineStatus) String() string { return string(s) }
+
 // ProposedRoutine — a detected pattern the system wants to nudge about on a
 // repeating interval. Status 'proposed' means awaiting human confirmation;
 // 'accepted' means the human confirmed and the tick loop now owns the schedule;
@@ -30,7 +53,7 @@ type ProposedRoutine struct {
 	Action       string
 	Object       string
 	IntervalDays float64
-	Status       string // proposed | accepted | dismissed
+	Status       RoutineStatus
 	CreatedTs    time.Time
 	ReminderID   *int64
 	AcceptedTs   *time.Time
@@ -40,6 +63,7 @@ type ProposedRoutine struct {
 var (
 	ErrProposedRoutineNotFound = errors.New("store: proposed routine not found")
 	ErrProposedRoutineExists   = errors.New("store: proposed routine already exists for this action+object")
+	ErrRoutineStatus           = errors.New("store: unknown routine status")
 )
 
 // CreateProposedRoutine inserts a new proposed routine. Returns
@@ -51,6 +75,16 @@ var (
 // keep finding the pattern, and every re-propose is refused here. Maven is not
 // a nag.
 //
+// The object stays a local string. It is not resolved against Nexus and it
+// carries no canonical entity ref (asked on the PR 4 review, decided here,
+// Vikunja #410). Nexus owns identity for things the ecosystem acts on, and
+// nothing acts on a routine object: it is the word he used, replayed back to
+// him in a nudge, and compared only against itself for the UNIQUE key. Two
+// spellings of the same watering can are two routines, and that is the right
+// answer when the point is to say the sentence he would say. Canonical refs
+// arrive here only if a routine ever drives a Hexis call, which is Vikunja
+// #272, not this.
+//
 // Vikunja #43: this is called both from the voice fact-write path (for the
 // immediate spoken confirmation) and from the digestion tick's proactive
 // scan (cmd/mavend/tick.go's detectPatterns, via patterns.go's
@@ -102,8 +136,13 @@ func (s *Store) ListProposedRoutines(ctx context.Context) ([]ProposedRoutine, er
 }
 
 // ListProposedRoutinesByStatus returns routines in one status, newest first.
-// An empty status returns every row.
-func (s *Store) ListProposedRoutinesByStatus(ctx context.Context, status string) ([]ProposedRoutine, error) {
+// An empty status returns every row; an unknown one is refused rather than
+// silently answering with nothing, since a typo and a genuinely empty state
+// read the same otherwise.
+func (s *Store) ListProposedRoutinesByStatus(ctx context.Context, status RoutineStatus) ([]ProposedRoutine, error) {
+	if status != "" && !status.Valid() {
+		return nil, fmt.Errorf("%w: %q", ErrRoutineStatus, status)
+	}
 	q := `SELECT id, action, object, interval_days, status, created_ts, reminder_id, accepted_ts, last_fired_ts
 	        FROM proposed_routines`
 	var args []any

internal/store/proposed_routines_test.go

@@ -235,7 +235,7 @@ func TestListProposedRoutinesByStatus(t *testing.T) {
 	}
 
 	cases := []struct {
-		status string
+		status RoutineStatus
 		want   int
 	}{
 		{RoutineProposed, 0},
@@ -266,3 +266,59 @@ func TestLookupMissingProposedRoutine(t *testing.T) {
 		t.Fatal("want nil for missing routine")
 	}
 }
+
+// Every legal status must survive the database. The status column is written
+// by three different UPDATE statements with the value spelled inline, so a
+// constant that drifts from its SQL is exactly the failure this catches: the
+// row would come back in a state no Go code compares equal to.
+func TestRoutineStatusRoundTrip(t *testing.T) {
+	ctx := context.Background()
+	s := newTestStore(t)
+	now := time.Now().UTC()
+
+	write := map[RoutineStatus]func(id int64) error{
+		RoutineProposed:  func(int64) error { return nil },
+		RoutineAccepted:  func(id int64) error { return s.AcceptProposedRoutine(ctx, id, now) },
+		RoutineDismissed: func(id int64) error { return s.DismissProposedRoutine(ctx, id) },
+	}
+
+	for _, want := range RoutineStatuses {
+		if !want.Valid() {
+			t.Fatalf("%q is in RoutineStatuses but not Valid()", want)
+		}
+		object := "object-" + want.String()
+		id, err := s.CreateProposedRoutine(ctx, "полить", object, 3, now)
+		if err != nil {
+			t.Fatalf("CreateProposedRoutine(%s): %v", want, err)
+		}
+		if err := write[want](id); err != nil {
+			t.Fatalf("move to %s: %v", want, err)
+		}
+		got, err := s.LookupProposedRoutine(ctx, "полить", object)
+		if err != nil || got == nil {
+			t.Fatalf("LookupProposedRoutine(%s): %v", want, err)
+		}
+		if got.Status != want {
+			t.Errorf("status = %q, want %q", got.Status, want)
+		}
+		list, err := s.ListProposedRoutinesByStatus(ctx, want)
+		if err != nil {
+			t.Fatalf("ListProposedRoutinesByStatus(%s): %v", want, err)
+		}
+		if len(list) != 1 {
+			t.Errorf("status %s: listed %d rows, want 1", want, len(list))
+		}
+	}
+}
+
+// A typo used to read as "nothing is in that state", which is the same answer
+// a correct query gives on an empty table.
+func TestListByStatusRefusesAnUnknownStatus(t *testing.T) {
+	s := newTestStore(t)
+	if _, err := s.ListProposedRoutinesByStatus(context.Background(), "accpeted"); !errors.Is(err, ErrRoutineStatus) {
+		t.Fatalf("err = %v, want ErrRoutineStatus", err)
+	}
+	if RoutineStatus("accpeted").Valid() {
+		t.Error("a typo must not be Valid()")
+	}
+}