Close DV-01–04,07,09,13,14: unify operator-deck UX in server/web.

Standardize neon cyan on #00e8f5, wire SacredPageHeader across Builds/Path Tracer/LOTL, dedupe Pages.css, align Path Tracer chrome, drop dead wealth-deck CSS, add prefers-color-scheme shell + HelpTip, sidebar version from package.json build inject, and Vitest CSS regression guards.

server/internal/db/pathtrace_sessions.go

@@ -0,0 +1,73 @@
+package db
+
+import (
+	"database/sql"
+	"time"
+)
+
+// PathTraceSessionRow is one persisted Path Tracer session blob.
+type PathTraceSessionRow struct {
+	ID        string
+	CreatedAt time.Time
+	Payload   []byte
+}
+
+// UpsertPathTraceSession stores or replaces a session JSON blob.
+func (d *Database) UpsertPathTraceSession(id string, createdAt time.Time, payload []byte) error {
+	_, err := d.Exec(
+		`INSERT INTO pathtrace_sessions (id, created_at, payload)
+		 VALUES (?, ?, ?)
+		 ON CONFLICT(id) DO UPDATE SET created_at = excluded.created_at, payload = excluded.payload`,
+		id, createdAt.UTC().Format(time.RFC3339Nano), payload,
+	)
+	return err
+}
+
+// ListPathTraceSessions returns all session rows ordered by age.
+func (d *Database) ListPathTraceSessions() ([]PathTraceSessionRow, error) {
+	rows, err := d.Query(`SELECT id, created_at, payload FROM pathtrace_sessions ORDER BY created_at ASC`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var out []PathTraceSessionRow
+	for rows.Next() {
+		var row PathTraceSessionRow
+		var created string
+		if err := rows.Scan(&row.ID, &created, &row.Payload); err != nil {
+			return nil, err
+		}
+		row.CreatedAt, _ = time.Parse(time.RFC3339Nano, created)
+		if row.CreatedAt.IsZero() {
+			row.CreatedAt, _ = time.Parse("2006-01-02 15:04:05", created)
+		}
+		out = append(out, row)
+	}
+	return out, rows.Err()
+}
+
+// DeletePathTraceSession removes one session row.
+func (d *Database) DeletePathTraceSession(id string) error {
+	_, err := d.Exec(`DELETE FROM pathtrace_sessions WHERE id = ?`, id)
+	return err
+}
+
+// DeleteExpiredPathTraceSessions removes rows older than cutoff.
+func (d *Database) DeleteExpiredPathTraceSessions(cutoff time.Time) (int64, error) {
+	res, err := d.Exec(`DELETE FROM pathtrace_sessions WHERE created_at < ?`, cutoff.UTC().Format(time.RFC3339Nano))
+	if err != nil {
+		return 0, err
+	}
+	return res.RowsAffected()
+}
+
+// PathTraceSessionCount returns how many session rows exist.
+func (d *Database) PathTraceSessionCount() (int, error) {
+	var n int
+	err := d.QueryRow(`SELECT COUNT(*) FROM pathtrace_sessions`).Scan(&n)
+	if err == sql.ErrNoRows {
+		return 0, nil
+	}
+	return n, err
+}