refactor(shared): move parseModelString out of delegate-task to break cross-tool coupling

Move parseModelString into src/shared so callers can depend on a neutral module instead of reaching into delegate-task internals.

Cross-tool coupling violates module boundaries, and this keeps call-omo-agent plus runtime-fallback from importing through a sibling tool.

src/tools/delegate-task/category-resolver.ts

@@ -5,7 +5,7 @@ import type { FallbackEntry } from "../../shared/model-requirements"
 import { mergeCategories } from "../../shared/merge-categories"
 import { SISYPHUS_JUNIOR_AGENT } from "./sisyphus-junior-agent"
 import { resolveCategoryConfig } from "./categories"
-import { parseModelString } from "./model-string-parser"
+import { parseModelString } from "../../shared/model-string-parser"
 import { CATEGORY_MODEL_REQUIREMENTS } from "../../shared/model-requirements"
 import { normalizeFallbackModels, flattenToFallbackModelStrings } from "../../shared/model-resolver"
 import { buildFallbackChainFromModels, findMostSpecificFallbackEntry } from "../../shared/fallback-chain-from-models"

src/tools/delegate-task/model-selection.ts

@@ -4,7 +4,7 @@ import { fuzzyMatchModel } from "../../shared/model-availability"
 import { transformModelForProvider } from "../../shared/provider-model-id-transform"
 import { hasConnectedProvidersCache, hasProviderModelsCache, readConnectedProvidersCache } from "../../shared/connected-providers-cache"
 import { log } from "../../shared/logger"
-import { parseModelString, parseVariantFromModelID } from "./model-string-parser"
+import { parseModelString, parseVariantFromModelID } from "../../shared/model-string-parser"
 
 function isExplicitHighModel(model: string): boolean {
   return /(?:^|\/)[^/]+-high$/.test(model)

src/tools/delegate-task/model-string-parser.ts

@@ -1,63 +0,0 @@
-const KNOWN_VARIANTS = new Set([
-  "low",
-  "medium",
-  "high",
-  "xhigh",
-  "max",
-  "minimal",
-  "none",
-  "auto",
-  "thinking",
-])
-
-export function parseVariantFromModelID(rawModelID: string): { modelID: string; variant?: string } {
-  const trimmedModelID = rawModelID.trim()
-  if (!trimmedModelID) {
-    return { modelID: "" }
-  }
-
-  const parenthesizedVariant = trimmedModelID.match(/^(.*)\(([^()]+)\)\s*$/)
-  if (parenthesizedVariant) {
-    const modelID = parenthesizedVariant[1]?.trim() ?? ""
-    const variant = parenthesizedVariant[2]?.trim()
-    return variant ? { modelID, variant } : { modelID }
-  }
-
-  const spaceVariant = trimmedModelID.match(/^(.*\S)\s+([a-z][a-z0-9_-]*)$/i)
-  if (spaceVariant) {
-    const modelID = spaceVariant[1]?.trim() ?? ""
-    const variant = spaceVariant[2]?.trim().toLowerCase()
-    if (variant && KNOWN_VARIANTS.has(variant)) {
-      return { modelID, variant }
-    }
-  }
-
-  return { modelID: trimmedModelID }
-}
-
-export function parseModelString(
-  model: string,
-): { providerID: string; modelID: string; variant?: string } | undefined {
-  const trimmedModel = model.trim()
-  if (!trimmedModel) return undefined
-
-  const parts = trimmedModel.split("/")
-  if (parts.length < 2) {
-    return undefined
-  }
-
-  const providerID = parts[0]?.trim()
-  const rawModelID = parts.slice(1).join("/").trim()
-  if (!providerID || !rawModelID) {
-    return undefined
-  }
-
-  const parsedModel = parseVariantFromModelID(rawModelID)
-  if (!parsedModel.modelID) {
-    return undefined
-  }
-
-  return parsedModel.variant
-    ? { providerID, modelID: parsedModel.modelID, variant: parsedModel.variant }
-    : { providerID, modelID: parsedModel.modelID }
-}