feat(installer): auto-configure athena council members based on available providers

The installer now detects which providers the user has (Anthropic, OpenAI,
Google, Copilot, OpenCode Zen) and generates council member config for Athena.
Requires at least 2 distinct providers; skips council config otherwise.
This implements the documented claim in configurations.md.

src/cli/__snapshots__/model-fallback.test.ts.snap

@@ -4,6 +4,9 @@ exports[`generateModelConfig no providers available returns ULTIMATE_FALLBACK fo
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "opencode/glm-4.7-free",
+    },
     "atlas": {
       "model": "opencode/gpt-5-nano",
     },
@@ -68,6 +71,10 @@ exports[`generateModelConfig single native provider uses Claude models when only
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "model": "anthropic/claude-sonnet-4.6",
     },
@@ -139,6 +146,10 @@ exports[`generateModelConfig single native provider uses Claude models with isMa
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "model": "anthropic/claude-sonnet-4.6",
     },
@@ -211,6 +222,10 @@ exports[`generateModelConfig single native provider uses OpenAI models when only
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "openai/gpt-5.2",
+      "variant": "high",
+    },
     "atlas": {
       "model": "openai/gpt-5.4",
       "variant": "medium",
@@ -301,6 +316,10 @@ exports[`generateModelConfig single native provider uses OpenAI models with isMa
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "openai/gpt-5.2",
+      "variant": "high",
+    },
     "atlas": {
       "model": "openai/gpt-5.4",
       "variant": "medium",
@@ -391,6 +410,10 @@ exports[`generateModelConfig single native provider uses Gemini models when only
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "google/gemini-3-pro",
+      "variant": "high",
+    },
     "atlas": {
       "model": "opencode/gpt-5-nano",
     },
@@ -455,6 +478,10 @@ exports[`generateModelConfig single native provider uses Gemini models with isMa
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "google/gemini-3-pro",
+      "variant": "high",
+    },
     "atlas": {
       "model": "opencode/gpt-5-nano",
     },
@@ -519,6 +546,26 @@ exports[`generateModelConfig all native providers uses preferred models from fal
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "anthropic/claude-sonnet-4-5",
+            "name": "Claude",
+          },
+          {
+            "model": "openai/gpt-5.2",
+            "name": "GPT",
+          },
+          {
+            "model": "google/gemini-3-flash",
+            "name": "Gemini",
+          },
+        ],
+      },
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -723,6 +770,26 @@ exports[`generateModelConfig all native providers uses preferred models with isM
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "anthropic/claude-sonnet-4-5",
+            "name": "Claude",
+          },
+          {
+            "model": "openai/gpt-5.2",
+            "name": "GPT",
+          },
+          {
+            "model": "google/gemini-3-flash",
+            "name": "Gemini",
+          },
+        ],
+      },
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -925,6 +992,10 @@ exports[`generateModelConfig fallback providers uses OpenCode Zen models when on
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "opencode/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -1150,6 +1221,10 @@ exports[`generateModelConfig fallback providers uses OpenCode Zen models with is
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "opencode/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -1379,6 +1454,10 @@ exports[`generateModelConfig fallback providers uses GitHub Copilot models when
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "github-copilot/claude-opus-4.6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -1565,6 +1644,10 @@ exports[`generateModelConfig fallback providers uses GitHub Copilot models with
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "github-copilot/claude-opus-4.6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -1753,6 +1836,9 @@ exports[`generateModelConfig fallback providers uses ZAI model for librarian whe
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "zai-coding-plan/glm-4.7",
+    },
     "atlas": {
       "model": "opencode/gpt-5-nano",
     },
@@ -1814,6 +1900,9 @@ exports[`generateModelConfig fallback providers uses ZAI model for librarian wit
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "zai-coding-plan/glm-4.7",
+    },
     "atlas": {
       "model": "opencode/gpt-5-nano",
     },
@@ -1875,6 +1964,22 @@ exports[`generateModelConfig mixed provider scenarios uses Claude + OpenCode Zen
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "anthropic/claude-sonnet-4-5",
+            "name": "Claude",
+          },
+          {
+            "model": "opencode/claude-sonnet-4-5",
+            "name": "OpenCode Claude",
+          },
+        ],
+      },
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -2160,6 +2265,22 @@ exports[`generateModelConfig mixed provider scenarios uses OpenAI + Copilot comb
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "openai/gpt-5.2",
+            "name": "GPT",
+          },
+          {
+            "model": "github-copilot/gpt-5.2",
+            "name": "Copilot GPT",
+          },
+        ],
+      },
+      "model": "github-copilot/claude-opus-4.6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -2411,6 +2532,10 @@ exports[`generateModelConfig mixed provider scenarios uses Claude + ZAI combinat
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "model": "anthropic/claude-sonnet-4.6",
     },
@@ -2500,6 +2625,22 @@ exports[`generateModelConfig mixed provider scenarios uses Gemini + Claude combi
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "anthropic/claude-sonnet-4-5",
+            "name": "Claude",
+          },
+          {
+            "model": "google/gemini-3-flash",
+            "name": "Gemini",
+          },
+        ],
+      },
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "model": "anthropic/claude-sonnet-4.6",
     },
@@ -2636,6 +2777,22 @@ exports[`generateModelConfig mixed provider scenarios uses all fallback provider
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "github-copilot/gpt-5.2",
+            "name": "Copilot GPT",
+          },
+          {
+            "model": "opencode/claude-sonnet-4-5",
+            "name": "OpenCode Claude",
+          },
+        ],
+      },
+      "model": "github-copilot/claude-opus-4.6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -3027,6 +3184,34 @@ exports[`generateModelConfig mixed provider scenarios uses all providers togethe
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "anthropic/claude-sonnet-4-5",
+            "name": "Claude",
+          },
+          {
+            "model": "openai/gpt-5.2",
+            "name": "GPT",
+          },
+          {
+            "model": "google/gemini-3-flash",
+            "name": "Gemini",
+          },
+          {
+            "model": "github-copilot/gpt-5.2",
+            "name": "Copilot GPT",
+          },
+          {
+            "model": "opencode/claude-sonnet-4-5",
+            "name": "OpenCode Claude",
+          },
+        ],
+      },
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {
@@ -3581,6 +3766,34 @@ exports[`generateModelConfig mixed provider scenarios uses all providers with is
 {
   "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
   "agents": {
+    "athena": {
+      "council": {
+        "members": [
+          {
+            "model": "anthropic/claude-sonnet-4-5",
+            "name": "Claude",
+          },
+          {
+            "model": "openai/gpt-5.2",
+            "name": "GPT",
+          },
+          {
+            "model": "google/gemini-3-flash",
+            "name": "Gemini",
+          },
+          {
+            "model": "github-copilot/gpt-5.2",
+            "name": "Copilot GPT",
+          },
+          {
+            "model": "opencode/claude-sonnet-4-5",
+            "name": "OpenCode Claude",
+          },
+        ],
+      },
+      "model": "anthropic/claude-opus-4-6",
+      "variant": "max",
+    },
     "atlas": {
       "fallback_models": [
         {