feat(platform): add copilot/autopilot cost tracking via token_tracking.py

Copilot uses OpenRouter via a separate code path (not through the block
executor). This integrates PlatformCostLog into the shared
persist_and_record_usage() function which is called by both SDK and
baseline copilot paths, capturing:
- Every LLM turn (main conversation, title gen, context compression)
- Tokens (prompt + completion + cache)
- Actual USD cost when available (SDK path provides cost_usd)
- Session ID for correlation

autogpt_platform/backend/backend/copilot/token_tracking.py

@@ -4,12 +4,15 @@ Both the baseline (OpenRouter) and SDK (Anthropic) service layers need to:
   1. Append a ``Usage`` record to the session.
   2. Log the turn's token counts.
   3. Record weighted usage in Redis for rate-limiting.
+  4. Write a PlatformCostLog entry for admin cost tracking.
 
 This module extracts that common logic so both paths stay in sync.
 """
 
 import logging
 
+from backend.data.platform_cost import PlatformCostEntry, log_platform_cost_safe
+
 from .model import ChatSession, Usage
 from .rate_limit import record_token_usage
 
@@ -95,4 +98,45 @@ async def persist_and_record_usage(
         except Exception as usage_err:
             logger.warning(f"{log_prefix} Failed to record token usage: {usage_err}")
 
+    # Log to PlatformCostLog for admin cost dashboard
+    if user_id and total_tokens > 0:
+        cost_float = None
+        if cost_usd is not None:
+            try:
+                cost_float = float(cost_usd)
+            except (ValueError, TypeError):
+                pass
+
+        cost_microdollars = int(cost_float * 1_000_000) if cost_float else None
+        session_id = session.session_id if session else None
+
+        if cost_float is not None:
+            tracking_type = "cost_usd"
+            tracking_amount = cost_float
+        else:
+            tracking_type = "tokens"
+            tracking_amount = total_tokens
+
+        await log_platform_cost_safe(
+            PlatformCostEntry(
+                user_id=user_id,
+                graph_exec_id=session_id,
+                block_id="copilot",
+                block_name=f"copilot:{log_prefix.strip(' []')}".rstrip(":"),
+                provider="open_router",
+                credential_id="copilot_system",
+                cost_microdollars=cost_microdollars,
+                input_tokens=prompt_tokens,
+                output_tokens=completion_tokens,
+                model=None,
+                metadata={
+                    "tracking_type": tracking_type,
+                    "tracking_amount": tracking_amount,
+                    "cache_read_tokens": cache_read_tokens,
+                    "cache_creation_tokens": cache_creation_tokens,
+                    "source": "copilot",
+                },
+            )
+        )
+
     return total_tokens