Tasks: optional persona for LLM + research tasks (biases output voice)

Wire the existing built-in PERSONAS catalog through to scheduled tasks
the same way I wired it to reminder synthesis. Repurposes the
dormant scheduled_tasks.character_id column.

UI (static/js/tasks.js)
- New 'Persona' select in the LLM / Research task form, with the five
  built-in characters (socrates/razor/nietzsche/spark/odysseus) plus a
  default 'no persona' option. Pre-populates from existing.character_id
  on edit. Non-llm/research types explicitly clear it on save.

API (routes/task_routes.py)
- TaskCreate + TaskUpdate gain character_id: Optional[str].
- _task_to_dict echoes character_id back so the form can hydrate on
  edit. Update endpoint stores '' as None to allow clearing.

Runner (src/task_scheduler.py)
- When task.character_id is set and matches a built-in persona, prepend
  the persona prompt to the task system prompt so the model speaks in
  that voice while still knowing it's running a scheduled task.
- crew_member.personality still wins as the base; character_id stacks
  on top.

routes/task_routes.py

@@ -151,6 +151,7 @@ class TaskCreate(BaseModel):
     endpoint_url: Optional[str] = None
     then_task_id: Optional[str] = None            # chain: run this task after success
     notifications_enabled: Optional[bool] = None  # None lets action-specific defaults apply
+    character_id: Optional[str] = None             # built-in persona id (PERSONAS) — biases output voice
 
 
 class TaskUpdate(BaseModel):
@@ -171,6 +172,7 @@ class TaskUpdate(BaseModel):
     endpoint_url: Optional[str] = None
     then_task_id: Optional[str] = None
     notifications_enabled: Optional[bool] = None
+    character_id: Optional[str] = None
 
 
 def _display_task_name(t: ScheduledTask) -> str:
@@ -203,6 +205,7 @@ def _task_to_dict(t: ScheduledTask, include_last_run_result: bool = False) -> di
         "output_target": t.output_target,
         "session_id": t.session_id,
         "crew_member_id": getattr(t, "crew_member_id", None),
+        "character_id": getattr(t, "character_id", None),
         "model": t.model,
         "endpoint_url": t.endpoint_url,
         "run_count": t.run_count or 0,
@@ -552,6 +555,7 @@ def setup_task_routes(task_scheduler) -> APIRouter:
                 then_task_id=then_task_id,
                 webhook_token=webhook_token,
                 notifications_enabled=notifications_enabled,
+                character_id=(req.character_id or None),
             )
             db.add(task)
             db.commit()
@@ -705,6 +709,9 @@ def setup_task_routes(task_scheduler) -> APIRouter:
                 task.then_task_id = _validate_then_task_id(db, req.then_task_id, user, current_task_id=task.id)
             if req.notifications_enabled is not None:
                 task.notifications_enabled = bool(req.notifications_enabled)
+            if req.character_id is not None:
+                # Empty string clears the persona; non-empty stores the id.
+                task.character_id = req.character_id or None
             if req.cron_expression is not None:
                 if req.cron_expression:
                     try:

src/task_scheduler.py

@@ -1335,11 +1335,24 @@ class TaskScheduler:
             return await self._execute_checkin(task, crew, db, session_id, endpoint_url, model)
 
         # Build system prompt: crew member persona overrides the default.
+        # Built-in character_id (Socrates, Razor, etc.) further biases the
+        # voice — it prepends to whichever base prompt we landed on so the
+        # task still knows it's executing a scheduled task but in that
+        # character's tone.
         system_prompt = (
             (crew.personality or "").strip()
             if crew and crew.personality
             else "You are a helpful assistant executing a scheduled task. Use available tools to complete the task thoroughly."
         )
+        char_id = (getattr(task, "character_id", None) or "").strip()
+        if char_id:
+            try:
+                from src.reminder_personas import PERSONAS as _PERSONAS
+                char_prompt = _PERSONAS.get(char_id.lower())
+                if char_prompt:
+                    system_prompt = f"{char_prompt}\n\n{system_prompt}"
+            except Exception:
+                pass
         # Inject current time so the model knows what's past vs upcoming
         tz_name = _resolve_task_timezone(db, task)
         try:

static/js/tasks.js

@@ -1077,9 +1077,23 @@ function _showForm(existing, initTaskType, initTriggerType) {
     typeOpts.innerHTML = '';
     if (taskType === 'llm' || taskType === 'research') {
       const placeholder = taskType === 'research' ? 'What should be researched?' : 'What should the AI do?';
+      const _personaOpts = [
+        ['', 'Default (no persona)'],
+        ['socrates', 'Socrates'],
+        ['razor', 'Razor'],
+        ['nietzsche', 'Nietzsche'],
+        ['spark', 'Spark'],
+        ['odysseus', 'Odysseus'],
+      ];
+      const _curPersona = (existing?.character_id || '').toLowerCase();
+      const _personaOptsHtml = _personaOpts.map(([v, label]) =>
+        `<option value="${v}" ${v === _curPersona ? 'selected' : ''}>${label}</option>`).join('');
       typeOpts.innerHTML = `
         <label class="task-form-label">${taskType === 'research' ? 'Research question' : 'Prompt'}</label>
         <textarea id="task-form-prompt" class="task-form-input task-form-textarea" rows="4" placeholder="${placeholder}">${existing?.prompt || ''}</textarea>
+
+        <label class="task-form-label">Persona <span style="opacity:0.5;font-weight:normal;font-size:10px;">(optional — biases the output voice)</span></label>
+        <select id="task-form-persona" class="task-form-input">${_personaOptsHtml}</select>
       `;
     } else {
       typeOpts.innerHTML = `
@@ -1437,7 +1451,11 @@ function _showForm(existing, initTaskType, initTriggerType) {
         return;
       }
       payload.prompt = prompt;
+      const personaVal = document.getElementById('task-form-persona')?.value || '';
+      payload.character_id = personaVal;
     } else {
+      // Non-llm/research tasks: explicitly clear any persona on switch.
+      payload.character_id = '';
       const action = document.getElementById('task-form-action')?.value;
       if (!action) {
         if (uiModule) uiModule.showError('Select an action');