feat(model-settings-compat): add variant/reasoningEffort compatibility resolver

- Registry-based model family detection (provider-agnostic)
- Variant and reasoningEffort ladder downgrade logic
- Three-tier resolution: metadata override → family heuristic → unknown drop
- Comprehensive test suite covering all model families

src/config/schema/agent-overrides.ts

@@ -35,7 +35,7 @@ export const AgentOverrideConfigSchema = z.object({
     })
     .optional(),
   /** Reasoning effort level (OpenAI). Overrides category and default settings. */
-  reasoningEffort: z.enum(["low", "medium", "high", "xhigh"]).optional(),
+  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh"]).optional(),
   /** Text verbosity level. */
   textVerbosity: z.enum(["low", "medium", "high"]).optional(),
   /** Provider-specific options. Passed directly to OpenCode SDK. */

src/config/schema/categories.ts

@@ -16,7 +16,7 @@ export const CategoryConfigSchema = z.object({
       budgetTokens: z.number().optional(),
     })
     .optional(),
-  reasoningEffort: z.enum(["low", "medium", "high", "xhigh"]).optional(),
+  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh"]).optional(),
   textVerbosity: z.enum(["low", "medium", "high"]).optional(),
   tools: z.record(z.string(), z.boolean()).optional(),
   prompt_append: z.string().optional(),