Phase 7: telemetry and usage (daily rollup + week dashboard)

Build on Phases 1–6. Telemetry already arrived on
restrict/<device>/telemetry; this phase stores it in a daily rollup and
shows it.

- store: migration 003 adds telemetry_daily (device, day, app seconds,
  site seconds). InsertTelemetry maintains the affected days in the same
  transaction; RebuildRollups backfills and repairs it. UsageRange and
  TopUsage serve the week grid and top lists. CapAudit enforces the
  size-capped append-only audit log from AGENTS.md §7.
- web: GET /devices/{id}/usage — Monday-to-Sunday totals plus the top 10
  apps and top 10 sites, using CSP-safe native <progress> bars.
- theme.js: light/dark from the OS preference, with a nav toggle, loaded
  as an external script so the strict CSP still holds.
- cmd/control: `rollup` subcommand; rollup rebuild and audit cap at
  start-up and every 15 minutes.
- Version 0.5.0-phase7 (compose, Makefile, docs).

Tests: go test ./... and go vet ./... pass in golang:1.25-alpine.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

internal/web/static/theme.js

@@ -0,0 +1,55 @@
+// Theme controller. The design tokens ship both palettes; nothing switches
+// between them unless this runs. It follows the OS preference by default and
+// remembers an explicit choice. Loaded with defer from /static/, so it is
+// allowed by the page's `script-src 'self'` policy (no inline script).
+(function () {
+  "use strict";
+  var KEY = "webrestrict.theme";
+  var root = document.documentElement;
+  var media = window.matchMedia("(prefers-color-scheme: dark)");
+  var stored = null;
+  try {
+    stored = window.localStorage.getItem(KEY);
+  } catch (e) {
+    stored = null;
+  }
+
+  function apply() {
+    var theme = stored || (media.matches ? "dark" : "light");
+    root.setAttribute("data-theme", theme);
+    var buttons = document.querySelectorAll("[data-theme-toggle]");
+    for (var i = 0; i < buttons.length; i++) {
+      buttons[i].textContent = theme === "dark" ? "Light" : "Dark";
+      buttons[i].setAttribute(
+        "aria-label",
+        "Switch to " + (theme === "dark" ? "light" : "dark") + " theme"
+      );
+    }
+  }
+
+  document.addEventListener("click", function (event) {
+    var target = event.target && event.target.closest
+      ? event.target.closest("[data-theme-toggle]")
+      : null;
+    if (!target) {
+      return;
+    }
+    stored = root.getAttribute("data-theme") === "dark" ? "light" : "dark";
+    try {
+      window.localStorage.setItem(KEY, stored);
+    } catch (e) {
+      /* private mode: the choice just does not persist */
+    }
+    apply();
+  });
+
+  if (media.addEventListener) {
+    media.addEventListener("change", function () {
+      if (!stored) {
+        apply();
+      }
+    });
+  }
+
+  apply();
+})();