refactor: enhance TimerPage layout and functionality; update theme and tokens for improved design consistency

- Refactored TimerPage component to improve layout and user experience.
- Updated theme configuration to utilize design tokens for better maintainability.
- Introduced new tokens for colors and typography to align with design principles.
- Simplified state management and improved timer functionality.
- Enhanced accessibility and responsiveness of UI elements.

backend/app/sources/jira.py

@@ -6,8 +6,8 @@ over from jira-helper's client. The difference is the query: jira-helper asks
 "what is due today", this asks "what is open at all", because you need
 something to start a pomodoro on even when nothing is due.
 
-Writing back is new here: finishing a Jira-backed pomodoro task transitions the
-issue to Done, so the app is not a second place to keep your task list in sync.
+Nothing is written back: you close an issue in Jira, and the next refresh
+notices it has left the "open issues" query. One owner per task.
 """
 
 from __future__ import annotations
@@ -110,45 +110,6 @@ class JiraSource:
         me = self._request("GET", "/rest/api/3/myself") or {}
         return f"{me.get('displayName', 'unknown')} on {self._base_url}"
 
-    def complete(self, item: TodoItem) -> bool:
-        """Transition the issue into a Done-category status.
-
-        Jira has no generic "close" verb: every project defines its own workflow,
-        so we ask the issue which transitions it offers and pick the one named in
-        the settings, else any transition landing in the Done category.
-        """
-        if not self._config.writeback_done:
-            return False
-        key = item.external_id
-        data = self._request("GET", f"/rest/api/3/issue/{key}/transitions") or {}
-        transitions = data.get("transitions", [])
-        wanted = self._config.done_transition_name.strip().lower()
-
-        chosen = next(
-            (t for t in transitions if (t.get("name") or "").lower() == wanted),
-            None,
-        ) or next(
-            (
-                t
-                for t in transitions
-                if ((t.get("to") or {}).get("statusCategory") or {}).get("key") == "done"
-            ),
-            None,
-        )
-        if chosen is None:
-            raise SourceError(
-                f"{key} has no transition to a Done status"
-                + (f" named {self._config.done_transition_name!r}" if wanted else "")
-                + ". Available: "
-                + ", ".join(t.get("name", "?") for t in transitions)
-            )
-        self._request(
-            "POST",
-            f"/rest/api/3/issue/{key}/transitions",
-            json={"transition": {"id": chosen["id"]}},
-        )
-        return True
-
     def close(self) -> None:
         self._client.close()