Implement LLM-WP-0007: Kimi K3 default and EUR spend reporting

Add moonshotai/kimi-k3 as OpenRouter basemodel default after live smoke,
USD→EUR cost conversion, append-only usage ledger, and CLI run/cost/spend
week commands with token and euro reporting.

llm_connect/__init__.py

@@ -8,7 +8,7 @@ Quick start::
 
     from llm_connect import create_adapter
 
-    adapter = create_adapter("openrouter", model="anthropic/claude-sonnet-4")
+    adapter = create_adapter("openrouter", model="moonshotai/kimi-k3")
     response = adapter.execute_prompt(prompt, run_config)
 """
 
@@ -16,6 +16,7 @@ from llm_connect.adapter import ErrorLLMAdapter, LLMAdapter, MockLLMAdapter
 from llm_connect.claude_code import ClaudeCodeAdapter
 from llm_connect.config import LLMConfig, load_config
 from llm_connect.costs import CostEstimate, CostModel, estimate_cost
+from llm_connect.fx import FxRate, resolve_fx_rate
 from llm_connect.embedding_adapter import EmbeddingAdapter
 from llm_connect.embedding_cache import EmbeddingCache
 from llm_connect.embedding_factory import create_embedding_adapter
@@ -71,6 +72,15 @@ from llm_connect.similarity import (
     find_similar_pairs,
     similarity_matrix,
 )
+from llm_connect.usage import (
+    UsageEvent,
+    UsageLedger,
+    UsageSummary,
+    default_usage_ledger_path,
+    event_from_response,
+    maybe_record_usage,
+    week_window,
+)
 
 __all__ = [
     "RunConfig",
@@ -120,6 +130,15 @@ __all__ = [
     "CostEstimate",
     "CostModel",
     "estimate_cost",
+    "FxRate",
+    "resolve_fx_rate",
+    "UsageEvent",
+    "UsageLedger",
+    "UsageSummary",
+    "default_usage_ledger_path",
+    "event_from_response",
+    "maybe_record_usage",
+    "week_window",
     "TokenEstimate",
     "Observation",
     "ProblemClass",