Rank captured tasks by what he actually said (#129)

Ordering is computed, not generated. Asking a 1.7B which of his tasks
matters most produces a fluent opinion with no basis in anything, and a
confidently wrong priority is worse than none — same posture as the
behaviour profile in internal/memory, which counts instead of summarising.

internal/tasks is a pure package (no ipc, no store, no cgo) holding the
score, the order and the Russian rendering, so the spoken list and the
/tasks page cannot drift. Four signals, all of them things he stated:
deadline (overdue > today > tomorrow > this week), stated urgency, age
with a cap so nothing rots at the bottom, and confirmed work always
ahead of mail-derived candidates. A task with no due date and no weight
scores nothing and carries no reason string — inventing a "потому что"
about a priority he never set is the failure mode this avoids.

Capture now picks up urgency he says out loud ("добавь в задачи срочно
оплатить интернет"), stripping the marker from the task text, and the web
add form offers the same three rungs. Ranking is a read: it sorts and
renders, never writes, schedules or announces.

cmd/mavweb/main.go

@@ -25,6 +25,7 @@ import (
 	"github.com/kami/maven/internal/audio"
 	"github.com/kami/maven/internal/ipc"
 	"github.com/kami/maven/internal/pattern"
+	"github.com/kami/maven/internal/tasks"
 	"github.com/kami/maven/internal/voice"
 	"github.com/kami/maven/internal/webauthn"
 )
@@ -840,6 +841,10 @@ type taskRow struct {
 	Due      string
 	Created  string
 	Resolved string
+	// Why — the ranker's reason for this row's position (Vikunja #129), in
+	// Russian, empty when nothing distinguished the task. Blank is the honest
+	// rendering: he never said this one mattered more.
+	Why string
 }
 
 // handleTasks serves the task review surface (GET) and the four writes it
@@ -878,20 +883,46 @@ func handleTasks(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI) {
 		http.Error(w, "tasks error: "+err.Error(), http.StatusBadGateway)
 		return
 	}
-	var cands, open, resolved []taskRow
+	// Live rows are ordered by the same ranker the spoken list uses, so the page
+	// and the voice reply can never disagree about what comes first. Resolved
+	// rows keep store order (newest first) — ranking finished work is pointless.
+	var live []tasks.Item
+	var resolved []taskRow
 	for _, t := range all {
+		switch t.Status {
+		case "candidate", "open":
+			live = append(live, tasks.Item{
+				ID: t.ID, Text: t.Text, Status: t.Status,
+				Created: t.CreatedTs, Due: t.Due, Weight: t.Weight,
+			})
+		default:
+			resolved = append(resolved, taskRow{
+				ID: t.ID, Text: t.Text, Source: t.Source, Evidence: t.Evidence,
+				Status: t.Status, Created: fmtTaskTime(&t.CreatedTs),
+				Due: fmtTaskDate(t.Due), Resolved: fmtTaskTime(t.Resolved),
+			})
+		}
+	}
+	byID := make(map[int64]ipc.Task, len(all))
+	for _, t := range all {
+		byID[t.ID] = t
+	}
+	var cands, open []taskRow
+	for _, r := range tasks.Rank(live, time.Now()) {
+		t := byID[r.ID]
 		row := taskRow{
 			ID: t.ID, Text: t.Text, Source: t.Source, Evidence: t.Evidence,
 			Status: t.Status, Created: fmtTaskTime(&t.CreatedTs),
 			Due: fmtTaskDate(t.Due), Resolved: fmtTaskTime(t.Resolved),
+			Why: r.Reason,
 		}
-		switch t.Status {
-		case "candidate":
+		if t.Status == "candidate" {
+			// A candidate's due date is Maven's reading of a mail, so its
+			// ranking reason is not shown as if he had set a priority.
+			row.Why = ""
 			cands = append(cands, row)
-		case "open":
+		} else {
 			open = append(open, row)
-		default:
-			resolved = append(resolved, row)
 		}
 	}
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
@@ -916,6 +947,18 @@ func applyTaskPost(ctx context.Context, core ipc.CoreAPI, r *http.Request) (stri
 			return "", errors.New("empty task text")
 		}
 		req := ipc.CaptureTaskReq{Text: text, Source: "tap:web", Status: "open", Ts: time.Now()}
+		// Importance is his, stated on the form. Out-of-range values are
+		// clamped rather than rejected — a bad select is not worth a 400.
+		if v := r.FormValue("weight"); v != "" {
+			var wgt int
+			if n, _ := fmt.Sscanf(v, "%d", &wgt); n != 1 || wgt < 0 {
+				return "", fmt.Errorf("bad weight %q", v)
+			}
+			if wgt > tasks.MaxWeight {
+				wgt = tasks.MaxWeight
+			}
+			req.Weight = wgt
+		}
 		if d := r.FormValue("due"); d != "" {
 			due, err := time.ParseInLocation("2006-01-02", d, time.Local)
 			if err != nil {