refactor(llm): route all tiers via OpenRouter, drop Anthropic SDK

Tutti i tier (S/A/B/C/D) ora passano per OpenRouter via OpenAI SDK.
Modelli Anthropic raggiungibili via prefisso `anthropic/...`.

- pyproject: rimosso `anthropic>=0.39` da deps + uv.lock
- config: rimosso `anthropic_api_key` field
- LLMClient: dispatch unico, single client OpenAI con base_url OpenRouter
- defaults S/A/B → `anthropic/claude-{opus-4-7,sonnet-4-6}`
- retry exceptions: solo openai.* (drop anthropic.*)
- test rinominati e adattati: tier S/A/B mockano OpenAI con prefisso `anthropic/`
- rimosso test `tier_S_without_anthropic_key_raises` (non più rilevante)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

uv.lock

@@ -139,25 +139,6 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/78/b6/6307fbef88d9b5ee7421e68d78a9f162e0da4900bc5f5793f6d3d0e34fb8/annotated_types-0.7.0-py3-none-any.whl", hash = "sha256:1f02e8b43a8fbbc3f3e0d4f0f4bfc8131bcb4eebe8849b8e5c773f3a1c582a53", size = 13643, upload-time = "2024-05-20T21:33:24.1Z" },
 ]
 
-[[package]]
-name = "anthropic"
-version = "0.100.0"
-source = { registry = "https://pypi.org/simple" }
-dependencies = [
-    { name = "anyio" },
-    { name = "distro" },
-    { name = "docstring-parser" },
-    { name = "httpx" },
-    { name = "jiter" },
-    { name = "pydantic" },
-    { name = "sniffio" },
-    { name = "typing-extensions" },
-]
-sdist = { url = "https://files.pythonhosted.org/packages/9c/2d/24caf0ff727cba2ed863925017c8f93463a2ea6224a0efe5626e672bc3d2/anthropic-0.100.0.tar.gz", hash = "sha256:650dee9e023afb16395939ee4104bbc21f966b380210119fb91122c12099c79a", size = 758255, upload-time = "2026-05-06T15:07:13.578Z" }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/5d/a0/c775c59ab9445ecabb57ef3d5c24027de060139189a9e312ef9ef889a665/anthropic-0.100.0-py3-none-any.whl", hash = "sha256:1c15769efa15d8fd5c1ebf900e25c57e3ee540f8554a29aa56e4edefffe2951d", size = 753596, upload-time = "2026-05-06T15:07:12.106Z" },
-]
-
 [[package]]
 name = "anyio"
 version = "4.13.0"
@@ -467,15 +448,6 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/12/b3/231ffd4ab1fc9d679809f356cebee130ac7daa00d6d6f3206dd4fd137e9e/distro-1.9.0-py3-none-any.whl", hash = "sha256:7bffd925d65168f85027d8da9af6bddab658135b840670a223589bc0c8ef02b2", size = 20277, upload-time = "2023-12-24T09:54:30.421Z" },
 ]
 
-[[package]]
-name = "docstring-parser"
-version = "0.18.0"
-source = { registry = "https://pypi.org/simple" }
-sdist = { url = "https://files.pythonhosted.org/packages/e0/4d/f332313098c1de1b2d2ff91cf2674415cc7cddab2ca1b01ae29774bd5fdf/docstring_parser-0.18.0.tar.gz", hash = "sha256:292510982205c12b1248696f44959db3cdd1740237a968ea1e2e7a900eeb2015", size = 29341, upload-time = "2026-04-14T04:09:19.867Z" }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/a7/5f/ed01f9a3cdffbd5a008556fc7b2a08ddb1cc6ace7effa7340604b1d16699/docstring_parser-0.18.0-py3-none-any.whl", hash = "sha256:b3fcbed555c47d8479be0796ef7e19c2670d428d72e96da63f3a40122860374b", size = 22484, upload-time = "2026-04-14T04:09:18.638Z" },
-]
-
 [[package]]
 name = "frozenlist"
 version = "1.8.0"
@@ -887,7 +859,6 @@ name = "multi-swarm"
 version = "0.1.0"
 source = { editable = "." }
 dependencies = [
-    { name = "anthropic" },
     { name = "ccxt" },
     { name = "httpx" },
     { name = "numpy" },
@@ -919,7 +890,6 @@ dev = [
 
 [package.metadata]
 requires-dist = [
-    { name = "anthropic", specifier = ">=0.39" },
     { name = "ccxt", specifier = ">=4.4" },
     { name = "httpx", specifier = ">=0.28" },
     { name = "numpy", specifier = ">=2.1" },