Put today's date (ET) in system prompt; stop hardcoding Simba's age

The model had no idea of the current date unless it remembered to call
the get_current_date tool, so relative/yearless dates (e.g. 'October')
got filled in from training data. build_system_prompt_with_memories now
prepends today's date (America/New_York) to every prompt, covering all
channels (web chat, iMessage, WhatsApp) and all date-related questions.

Simba's age is now computed from his birth date instead of a stale
hardcoded 'approximately 9 years 5 months'.

blueprints/conversation/memory.py

@@ -1,7 +1,19 @@
+from datetime import datetime
+from zoneinfo import ZoneInfo
+
 from .models import UserMemory
 from .prompts import SIMBA_SYSTEM_PROMPT
 
 
+def _date_header() -> str:
+    """Today's date in Eastern time, always known to the model without a tool call."""
+    now = datetime.now(ZoneInfo("America/New_York"))
+    return (
+        f"TODAY'S DATE: {now:%A, %B %d, %Y} (Eastern time). "
+        f"Interpret any relative or yearless dates (e.g. 'October', 'last month') relative to today's date.\n\n"
+    )
+
+
 async def get_memories_for_user(user_id: str) -> list[str]:
     """Return all memory content strings for a user, ordered by most recently updated."""
     memories = await UserMemory.filter(user_id=user_id).order_by("-updated_at")
@@ -10,10 +22,11 @@ async def get_memories_for_user(user_id: str) -> list[str]:
 
 async def build_system_prompt_with_memories(user_id: str) -> str:
     memories = await get_memories_for_user(user_id)
+    prompt = f"{_date_header()}{SIMBA_SYSTEM_PROMPT}"
     if not memories:
-        return SIMBA_SYSTEM_PROMPT
+        return prompt
     block = "\n".join(f"- {m}" for m in memories)
-    return f"{SIMBA_SYSTEM_PROMPT}\n\nUSER MEMORIES (facts the user has asked you to remember):\n{block}"
+    return f"{prompt}\n\nUSER MEMORIES (facts the user has asked you to remember):\n{block}"
 
 
 async def save_memory(user_id: str, content: str) -> str:

blueprints/conversation/prompts.py

@@ -1,10 +1,10 @@
 SIMBA_SYSTEM_PROMPT = """You are Simba, Ryan's helpful personal assistant. You're named after his orange cat. You have a warm, friendly personality with a light cat-themed touch, but your priority is always being genuinely useful — give thorough, detailed answers and think things through carefully. When asked about Simba the cat, you speak as him in first person. For everything else, you're just a great assistant who happens to have a cat's name.
 
-SIMBA FACTS (as of January 2026):
+SIMBA FACTS (as of January 2026; compute his current age from today's date):
 - Name: Simba
 - Species: Feline (Domestic Short Hair / American Short Hair)
 - Sex: Male, Neutered
-- Date of Birth: August 8, 2016 (approximately 9 years 5 months old)
+- Date of Birth: August 8, 2016
 - Color: Orange
 - Current Weight: 16 lbs (as of 1/8/2026)
 - Owner: Ryan Chen