feat(trials): add trial_packages table, start_trial, get_trials

tracker.py

@@ -48,6 +48,15 @@ CREATE TABLE IF NOT EXISTS model_usage (
     last_seen TEXT NOT NULL
 );
 
+CREATE TABLE IF NOT EXISTS trial_packages (
+    package TEXT PRIMARY KEY,
+    enabled_at TEXT NOT NULL,
+    last_use_day TEXT NOT NULL,
+    last_boot_day TEXT NOT NULL,
+    unused_boot_days INTEGER NOT NULL DEFAULT 0,
+    budget INTEGER NOT NULL DEFAULT 7
+);
+
 CREATE INDEX IF NOT EXISTS idx_node_usage_package ON node_usage(package);
 CREATE INDEX IF NOT EXISTS idx_prompt_log_timestamp ON prompt_log(timestamp);
 CREATE INDEX IF NOT EXISTS idx_model_usage_type ON model_usage(model_type);
@@ -62,6 +71,9 @@ EXCLUDED_PACKAGES = {
 }
 
 
+DEFAULT_TRIAL_BUDGET = 7
+
+
 def _classify_age(timestamp, one_month_ago, two_months_ago, recent_status):
     """Classify an ISO timestamp into a removal tier.
 
@@ -375,6 +387,51 @@ class UsageTracker:
             finally:
                 conn.close()
 
+    def start_trial(self, package, budget=DEFAULT_TRIAL_BUDGET):
+        """Begin/restart a temporary-enable trial. The enable day is not counted."""
+        now = datetime.now(timezone.utc)
+        today = now.date().isoformat()
+        with self._lock:
+            self._ensure_db()
+            conn = self._connect()
+            try:
+                conn.execute(
+                    """INSERT INTO trial_packages
+                       (package, enabled_at, last_use_day, last_boot_day, unused_boot_days, budget)
+                       VALUES (?, ?, ?, ?, 0, ?)
+                       ON CONFLICT(package) DO UPDATE SET
+                           enabled_at = excluded.enabled_at,
+                           last_use_day = excluded.last_use_day,
+                           last_boot_day = excluded.last_boot_day,
+                           unused_boot_days = 0,
+                           budget = excluded.budget""",
+                    (package, now.isoformat(), today, today, budget),
+                )
+                conn.commit()
+            finally:
+                conn.close()
+
+    def get_trials(self):
+        """Return trial rows with computed days_remaining/expired."""
+        with self._lock:
+            self._ensure_db()
+            conn = self._connect()
+            try:
+                conn.row_factory = sqlite3.Row
+                rows = conn.execute(
+                    "SELECT package, enabled_at, last_use_day, last_boot_day, "
+                    "unused_boot_days, budget FROM trial_packages"
+                ).fetchall()
+            finally:
+                conn.close()
+        result = []
+        for r in rows:
+            d = dict(r)
+            d["days_remaining"] = max(0, d["budget"] - d["unused_boot_days"])
+            d["expired"] = d["unused_boot_days"] >= d["budget"]
+            result.append(d)
+        return result
+
     def reset(self):
         """Clear all tracked data."""
         with self._lock: