feat: add kimi-k2.5 to agent fallback chains and update model catalog

- sisyphus: opus → kimi-k2.5 → glm-4.7 → gpt-5.2-codex → gemini-3-pro
- atlas: sonnet-4-5 → kimi-k2.5 → gpt-5.2 → gemini-3-pro
- prometheus/metis: opus → kimi-k2.5 → gpt-5.2 → gemini-3-pro
- multimodal-looker: gemini-flash → gpt-5.2 → glm-4.6v → kimi-k2.5 → haiku → gpt-5-nano
- visual-engineering: remove gpt-5.2 from chain
- ultrabrain: reorder to gpt-5.2-codex → gemini-3-pro → opus
- Add cross-provider fuzzy match for model resolution
- Update all documentation (AGENTS.md, features.md, configurations.md, category-skill-guide.md)

src/shared/model-resolver.ts

@@ -117,6 +117,7 @@ export function resolveModelWithFallback(
 			}
 		} else {
 			for (const entry of fallbackChain) {
+				// Step 1: Try with provider filter (preferred providers first)
 				for (const provider of entry.providers) {
 					const fullModel = `${provider}/${entry.model}`
 					const match = fuzzyMatchModel(fullModel, availableModels, [provider])
@@ -125,6 +126,17 @@ export function resolveModelWithFallback(
 						return { model: match, source: "provider-fallback", variant: entry.variant }
 					}
 				}
+
+				// Step 2: Try without provider filter (cross-provider fuzzy match)
+				const crossProviderMatch = fuzzyMatchModel(entry.model, availableModels)
+				if (crossProviderMatch) {
+					log("Model resolved via fallback chain (cross-provider fuzzy match)", {
+						model: entry.model,
+						match: crossProviderMatch,
+						variant: entry.variant,
+					})
+					return { model: crossProviderMatch, source: "provider-fallback", variant: entry.variant }
+				}
 			}
 			log("No available model found in fallback chain, falling through to system default")
 		}