Show trustworthy local-day activity totals (#90)

Add local-day activity summaries derived from UTC hour observations using
the system timezone, with durable storage in a new local_days table.
The collector derives local-day read/write totals after UTC aggregation;
the TUI displays them with timezone, completeness state, and coverage.

Schema: bump SCHEMA_VERSION to 3, add local_days table (migration 2→3
is pure addition, idempotent, preserves newer-schema refusal).

src/fenris/tui.py

@@ -1045,19 +1045,35 @@ class FenrisTuiApp(App):
         grid-rows: auto 10 auto 3;
         height: auto;
     }
+    #main-grid.local-day {
+        grid-size: 2 5;
+        grid-rows: auto 10 auto auto 3;
+    }
     #main-grid.paused {
         grid-size: 2 5;
         grid-rows: auto auto 10 auto 3;
     }
+    #main-grid.paused.local-day {
+        grid-size: 2 6;
+        grid-rows: auto auto 10 auto auto 3;
+    }
     #main-grid.constrained {
         grid-size: 1 4;
         grid-columns: 1fr;
         grid-rows: auto auto auto auto;
     }
+    #main-grid.constrained.local-day {
+        grid-size: 1 5;
+        grid-rows: auto auto auto auto auto;
+    }
     #main-grid.constrained.paused {
         grid-size: 1 5;
         grid-rows: auto auto auto auto auto;
     }
+    #main-grid.constrained.paused.local-day {
+        grid-size: 1 6;
+        grid-rows: auto auto auto auto auto auto;
+    }
     #main-grid.constrained #usage-history {
         display: none;
     }
@@ -1071,6 +1087,14 @@ class FenrisTuiApp(App):
         height: auto;
         min-height: 3;
     }
+    #local-day {
+        column-span: 2;
+        display: none;
+        border: round #555555;
+        padding: 0 1;
+        height: auto;
+        min-height: 3;
+    }
     #dashboard-scroll { height: 1fr; }
     #headline-band { column-span: 2; height: auto; min-height: 8; }
     #paused-banner {
@@ -1141,6 +1165,7 @@ class FenrisTuiApp(App):
                 yield DailyBarGraph(id="usage-history", classes="pane")
                 yield Static("", id="constrained-summary", classes="pane")
                 yield Static("", id="drive-health", classes="pane")
+                yield Static("", id="local-day", classes="pane")
                 yield Static("", id="service-strip", classes="pane")
                 yield Static("q Quit TUI", id="quit-rail")
 
@@ -1154,6 +1179,7 @@ class FenrisTuiApp(App):
         self.query_one("#usage-history").border_title = "Usage history"
         self.query_one("#constrained-summary").border_title = "Usage history"
         self.query_one("#drive-health").border_title = "Drive"
+        self.query_one("#local-day").border_title = "Local day"
         self.query_one("#service-strip").border_title = "Monitoring and actions"
         self._refresh_timer = self.set_interval(
             self.refresh_interval_s, self.on_refresh_tick
@@ -1277,6 +1303,11 @@ class FenrisTuiApp(App):
             self.query_one("#constrained-summary").update(
                 "[dim]Graph needs ≥80×24[/dim]\n" + message
             )
+        # Hide local-day widget when no data
+        local_day_widget = self.query_one("#local-day")
+        local_day_widget.styles.display = "none"
+        main_grid = self.query_one("#main-grid")
+        main_grid.remove_class("local-day")
 
     def _render_all_regions(self, conn: sqlite3.Connection, comp: StatusComposition) -> None:
         """Render all four regions from live store data."""
@@ -1355,6 +1386,9 @@ class FenrisTuiApp(App):
         )
         self.query_one("#drive-health").update(health_text)
 
+        # --- Local-day totals (issue #90) ---
+        self._render_local_day(conn)
+
     def _render_paused_banner(self, comp) -> None:
         """Show the high-contrast Deliberate disable block only when sanctioned.
 
@@ -1388,6 +1422,46 @@ class FenrisTuiApp(App):
         main_grid.remove_class("paused")
         main_grid.refresh(layout=True)
 
+    def _render_local_day(self, conn: sqlite3.Connection) -> None:
+        """Render the local-day activity totals widget (issue #90)."""
+        try:
+            from .tz_util import detect_system_tz
+            from .local_day import query_current_local_day
+            tz_name = detect_system_tz()
+            local = query_current_local_day(conn, self._clock_now, tz_name)
+        except Exception:
+            local = None
+
+        widget = self.query_one("#local-day")
+        main_grid = self.query_one("#main-grid")
+
+        if local is None:
+            widget.styles.display = "none"
+            main_grid.remove_class("local-day")
+            return
+
+        main_grid.add_class("local-day")
+        widget.styles.display = "block"
+
+        bw = local["bytes_written"]
+        br = local["bytes_read"]
+        partial = "" if local["complete"] else " · totals so far"
+        tz_display = "%s %s" % (local["tz_name"], local["tz_offset"])
+
+        text = (
+            "[bold]%s[/bold] %s%s\n"
+            " W %.3f GB · R %.3f GB · %.0f%% coverage"
+            % (
+                local["local_date"],
+                tz_display,
+                partial,
+                bw / 1e9,
+                br / 1e9,
+                local["coverage"] * 100,
+            )
+        )
+        widget.update(text)
+
     def _on_graph_drill(self, day: str) -> None:
         """Load hourly data when the graph enters drill-down mode."""
         graph = self.query_one("#usage-history")