Pin litellm to v1.82.3 and bump version to 0.5.3

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "headroom-ai"
-version = "0.5.2"
+version = "0.5.3"
 description = "The Context Optimization Layer for LLM Applications - Cut costs by 50-90%"
 readme = "README.md"
 license = "Apache-2.0"
@@ -47,7 +47,7 @@ dependencies = [
     # Core: lightweight compression (SmartCrusher, ContentRouter, CCR, TOIN)
     "tiktoken>=0.5.0",            # Tokenizer for all compressors
     "pydantic>=2.0.0",            # Config and data models
-    "litellm>=1.0.0",             # Model registry, pricing, and provider support
+    "litellm==1.82.3",            # Model registry, pricing, and provider support
     "click>=8.1.0",               # CLI framework
     "rich>=13.0.0",               # Rich terminal output
 ]
@@ -162,7 +162,7 @@ dev = [
     "pre-commit>=3.0.0",
     "openai>=1.0.0",
     "anthropic>=0.18.0",
-    "litellm>=1.0.0",
+    "litellm==1.82.3",
     "fastapi>=0.100.0",
     "uvicorn>=0.23.0",
     "httpx[http2]>=0.24.0",