refactor(open-sse): P3 provider registry — split into providers/registry/{id}.js

- 100 registry files: transport + models co-located per provider (Mongoose-style)
- providers/shared.js: shared Claude headers + OS/arch helpers (deduped)
- providers/models/helpers.js: withCodexReviewModels (kept dynamic)
- providers/index.js builds PROVIDERS + PROVIDER_MODELS = old API (content byte-for-byte)
- config/providers.js + providerModels.js → barrel re-export, keep accessors + runtime helpers
- Verified: PROVIDERS/MODELS/OAuth/alias byte-for-byte, golden translator tests pass, 0 new regression

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/__baseline__/alias-baseline.json

@@ -135,97 +135,97 @@
     "blackbox": "blackbox"
   },
   "idToAlias": {
-    "claude": "cc",
-    "gemini": "gemini",
-    "gemini-cli": "gc",
-    "codex": "cx",
-    "qwen": "qw",
-    "iflow": "if",
-    "qoder": "qd",
-    "antigravity": "ag",
-    "openrouter": "openrouter",
-    "openai": "openai",
-    "vercel-ai-gateway": "vercel-ai-gateway",
-    "glm": "glm",
-    "glm-cn": "glm-cn",
-    "kimi": "kimi",
-    "minimax": "minimax",
-    "minimax-cn": "minimax-cn",
+    "agentrouter": "agentrouter",
+    "ai21": "ai21",
+    "aimlapi": "aimlapi",
     "alicode": "alicode",
     "alicode-intl": "alicode-intl",
-    "volcengine-ark": "volcengine-ark",
-    "byteplus": "byteplus",
-    "github": "gh",
-    "kiro": "kr",
-    "cursor": "cu",
-    "kimi-coding": "kmc",
-    "kilocode": "kc",
-    "cline": "cl",
-    "nvidia": "nvidia",
     "anthropic": "anthropic",
-    "deepseek": "deepseek",
-    "commandcode": "commandcode",
-    "groq": "groq",
-    "xai": "xai",
-    "mistral": "mistral",
-    "perplexity": "perplexity",
-    "together": "together",
-    "fireworks": "fireworks",
-    "cerebras": "cerebras",
-    "cohere": "cohere",
-    "nebius": "nebius",
-    "siliconflow": "siliconflow",
-    "hyperbolic": "hyperbolic",
-    "deepgram": "deepgram",
+    "antigravity": "ag",
     "assemblyai": "assemblyai",
-    "nanobanana": "nanobanana",
+    "azure": "azure",
+    "baseten": "baseten",
+    "bazaarlink": "bazaarlink",
+    "blackbox": "blackbox",
+    "byteplus": "byteplus",
+    "bytez": "bytez",
+    "cerebras": "cerebras",
     "chutes": "chutes",
+    "claude": "cc",
+    "cline": "cl",
+    "cloudflare-ai": "cloudflare-ai",
+    "codebuddy": "codebuddy",
+    "codex": "cx",
+    "cohere": "cohere",
+    "commandcode": "commandcode",
+    "completions": "completions",
+    "cursor": "cu",
+    "deepgram": "deepgram",
+    "deepinfra": "deepinfra",
+    "deepseek": "deepseek",
+    "enally": "enally",
+    "fireworks": "fireworks",
+    "freetheai": "freetheai",
+    "gemini": "gemini",
+    "gemini-cli": "gc",
+    "github": "gh",
+    "gitlab": "gitlab",
+    "glhf": "glhf",
+    "glm": "glm",
+    "glm-cn": "glm-cn",
+    "grok-web": "grok-web",
+    "groq": "groq",
+    "hyperbolic": "hyperbolic",
+    "iflow": "if",
+    "inference-net": "inference-net",
+    "kilocode": "kc",
+    "kimi": "kimi",
+    "kimi-coding": "kmc",
+    "kiro": "kr",
+    "kluster": "kluster",
+    "lepton": "lepton",
+    "llm7": "llm7",
+    "longcat": "longcat",
+    "mimo-free": "mmf",
+    "minimax": "minimax",
+    "minimax-cn": "minimax-cn",
+    "mistral": "mistral",
+    "mmf": "mmf",
+    "modal": "modal",
+    "morph": "morph",
+    "nanobanana": "nanobanana",
+    "nebius": "nebius",
+    "nlpcloud": "nlpcloud",
+    "nous-research": "nous-research",
+    "novita": "novita",
+    "nscale": "nscale",
+    "nvidia": "nvidia",
     "ollama": "ollama",
     "ollama-local": "ollama-local",
-    "vertex": "vertex",
-    "vertex-partner": "vertex-partner",
-    "gitlab": "gitlab",
-    "codebuddy": "codebuddy",
+    "openai": "openai",
     "opencode": "oc",
     "opencode-go": "opencode-go",
-    "grok-web": "grok-web",
+    "openrouter": "openrouter",
+    "perplexity": "perplexity",
     "perplexity-web": "perplexity-web",
-    "azure": "azure",
-    "cloudflare-ai": "cloudflare-ai",
-    "xiaomi-mimo": "xiaomi-mimo",
-    "mimo-free": "mmf",
-    "mmf": "mmf",
-    "xiaomi-tokenplan": "xiaomi-tokenplan",
-    "agentrouter": "agentrouter",
-    "aimlapi": "aimlapi",
-    "novita": "novita",
-    "modal": "modal",
-    "reka": "reka",
-    "nlpcloud": "nlpcloud",
-    "bazaarlink": "bazaarlink",
-    "completions": "completions",
-    "enally": "enally",
-    "freetheai": "freetheai",
-    "llm7": "llm7",
-    "lepton": "lepton",
-    "kluster": "kluster",
-    "ai21": "ai21",
-    "inference-net": "inference-net",
     "predibase": "predibase",
-    "bytez": "bytez",
-    "morph": "morph",
-    "longcat": "longcat",
-    "puter": "puter",
-    "uncloseai": "uncloseai",
-    "scaleway": "scaleway",
-    "deepinfra": "deepinfra",
-    "sambanova": "sambanova",
-    "nscale": "nscale",
-    "baseten": "baseten",
     "publicai": "publicai",
-    "nous-research": "nous-research",
-    "glhf": "glhf",
-    "blackbox": "blackbox"
+    "puter": "puter",
+    "qoder": "qd",
+    "qwen": "qw",
+    "reka": "reka",
+    "sambanova": "sambanova",
+    "scaleway": "scaleway",
+    "siliconflow": "siliconflow",
+    "together": "together",
+    "uncloseai": "uncloseai",
+    "vercel-ai-gateway": "vercel-ai-gateway",
+    "vertex": "vertex",
+    "vertex-partner": "vertex-partner",
+    "volcengine-ark": "volcengine-ark",
+    "xai": "xai",
+    "xiaomi-mimo": "xiaomi-mimo",
+    "xiaomi-tokenplan": "xiaomi-tokenplan"
   },
   "modelKeys": [
     "ag",