feat(footer): help popover shows license state + Activate link

- Bump version to 3.0 (src/__init__.py).
- Switch support address to support@unalogix.com.
- Help popover now includes a License section that reads
  ``src.license.current_state()``:
  * When activated + valid: name + expiry date + days remaining.
  * Otherwise: "Not activated" + an ``Activate now →`` link
    pointing at ``./activate``.
  License-state queries are wrapped so a corrupted license file
  can't take the footer down — it falls through to the inactive
  branch.
- Popover HTML is now built in Python (so the license branch
  lives in one place) and passed to the JS as a single string.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/i18n/packs/en.json

@@ -178,6 +178,11 @@
     "help_title": "DataTools",
     "help_version": "Version {version}",
     "help_support": "Support: {email}",
+    "help_license_label": "License",
+    "help_license_inactive": "Not activated",
+    "help_license_active": "{name}",
+    "help_license_expires": "Expires {date} ({days} days)",
+    "help_activate_link": "Activate now →",
     "help_dismiss": "Close"
   }
 }