feat: initial model catalog with 196 models across 39 providers

Community-maintained TOML catalog for LibreFang. New models can be added
via PR without requiring a LibreFang binary release.

Includes validation script, bilingual docs, and GitHub templates.

providers/xai.toml

@@ -0,0 +1,126 @@
+# xAI — https://x.ai
+# Models: 9
+
+[provider]
+id = "xai"
+display_name = "xAI"
+api_key_env = "XAI_API_KEY"
+base_url = "https://api.x.ai/v1"
+key_required = true
+
+[[models]]
+id = "grok-4-0709"
+display_name = "Grok 4"
+tier = "frontier"
+context_window = 256000
+max_output_tokens = 32768
+input_cost_per_m = 3.0
+output_cost_per_m = 15.0
+supports_tools = true
+supports_vision = true
+supports_streaming = true
+aliases = ["grok", "grok-4"]
+
+[[models]]
+id = "grok-4-fast-reasoning"
+display_name = "Grok 4 Fast Reasoning"
+tier = "smart"
+context_window = 256000
+max_output_tokens = 32768
+input_cost_per_m = 1.0
+output_cost_per_m = 5.0
+supports_tools = true
+supports_vision = false
+supports_streaming = true
+aliases = []
+
+[[models]]
+id = "grok-4-fast-non-reasoning"
+display_name = "Grok 4 Fast Non-Reasoning"
+tier = "smart"
+context_window = 256000
+max_output_tokens = 32768
+input_cost_per_m = 1.0
+output_cost_per_m = 5.0
+supports_tools = true
+supports_vision = false
+supports_streaming = true
+aliases = []
+
+[[models]]
+id = "grok-4-1-fast-reasoning"
+display_name = "Grok 4.1 Fast Reasoning"
+tier = "fast"
+context_window = 2000000
+max_output_tokens = 32768
+input_cost_per_m = 0.20
+output_cost_per_m = 0.50
+supports_tools = true
+supports_vision = false
+supports_streaming = true
+aliases = ["grok-fast"]
+
+[[models]]
+id = "grok-4-1-fast-non-reasoning"
+display_name = "Grok 4.1 Fast Non-Reasoning"
+tier = "fast"
+context_window = 2000000
+max_output_tokens = 32768
+input_cost_per_m = 0.20
+output_cost_per_m = 0.50
+supports_tools = true
+supports_vision = false
+supports_streaming = true
+aliases = []
+
+[[models]]
+id = "grok-3"
+display_name = "Grok 3"
+tier = "frontier"
+context_window = 131072
+max_output_tokens = 32768
+input_cost_per_m = 3.0
+output_cost_per_m = 15.0
+supports_tools = true
+supports_vision = true
+supports_streaming = true
+aliases = ["grok3"]
+
+[[models]]
+id = "grok-3-mini"
+display_name = "Grok 3 Mini"
+tier = "balanced"
+context_window = 131072
+max_output_tokens = 32768
+input_cost_per_m = 0.30
+output_cost_per_m = 0.50
+supports_tools = true
+supports_vision = false
+supports_streaming = true
+aliases = []
+
+[[models]]
+id = "grok-2"
+display_name = "Grok 2"
+tier = "smart"
+context_window = 131072
+max_output_tokens = 32768
+input_cost_per_m = 2.0
+output_cost_per_m = 10.0
+supports_tools = true
+supports_vision = true
+supports_streaming = true
+aliases = []
+
+[[models]]
+id = "grok-2-mini"
+display_name = "Grok 2 Mini"
+tier = "fast"
+context_window = 131072
+max_output_tokens = 32768
+input_cost_per_m = 0.30
+output_cost_per_m = 0.50
+supports_tools = true
+supports_vision = false
+supports_streaming = true
+aliases = ["grok-mini"]