refactor: wave 1 - extract leaf modules, rename catch-all files, split index.ts hooks

- Split 25+ index.ts files into hook.ts + extracted modules
- Rename all catch-all utils.ts/helpers.ts to domain-specific names
- Split src/tools/lsp/ into ~15 focused modules
- Split src/tools/delegate-task/ into ~18 focused modules
- Separate shared types from implementation
- 155 files changed, 60+ new files created
- All typecheck clean, 61 tests pass

src/agents/builtin-agents/hephaestus-agent.ts

@@ -0,0 +1,88 @@
+import type { AgentConfig } from "@opencode-ai/sdk"
+import type { AgentOverrides } from "../types"
+import type { CategoryConfig } from "../../config/schema"
+import type { AvailableAgent, AvailableCategory, AvailableSkill } from "../dynamic-agent-prompt-builder"
+import { AGENT_MODEL_REQUIREMENTS, isAnyProviderConnected } from "../../shared"
+import { createHephaestusAgent } from "../hephaestus"
+import { createEnvContext } from "../env-context"
+import { applyCategoryOverride, mergeAgentConfig } from "./agent-overrides"
+import { applyModelResolution, getFirstFallbackModel } from "./model-resolution"
+
+export function maybeCreateHephaestusConfig(input: {
+  disabledAgents: string[]
+  agentOverrides: AgentOverrides
+  availableModels: Set<string>
+  systemDefaultModel?: string
+  isFirstRunNoCache: boolean
+  availableAgents: AvailableAgent[]
+  availableSkills: AvailableSkill[]
+  availableCategories: AvailableCategory[]
+  mergedCategories: Record<string, CategoryConfig>
+  directory?: string
+}): AgentConfig | undefined {
+  const {
+    disabledAgents,
+    agentOverrides,
+    availableModels,
+    systemDefaultModel,
+    isFirstRunNoCache,
+    availableAgents,
+    availableSkills,
+    availableCategories,
+    mergedCategories,
+    directory,
+  } = input
+
+  if (disabledAgents.includes("hephaestus")) return undefined
+
+  const hephaestusOverride = agentOverrides["hephaestus"]
+  const hephaestusRequirement = AGENT_MODEL_REQUIREMENTS["hephaestus"]
+  const hasHephaestusExplicitConfig = hephaestusOverride !== undefined
+
+  const hasRequiredProvider =
+    !hephaestusRequirement?.requiresProvider ||
+    hasHephaestusExplicitConfig ||
+    isFirstRunNoCache ||
+    isAnyProviderConnected(hephaestusRequirement.requiresProvider, availableModels)
+
+  if (!hasRequiredProvider) return undefined
+
+  let hephaestusResolution = applyModelResolution({
+    userModel: hephaestusOverride?.model,
+    requirement: hephaestusRequirement,
+    availableModels,
+    systemDefaultModel,
+  })
+
+  if (isFirstRunNoCache && !hephaestusOverride?.model) {
+    hephaestusResolution = getFirstFallbackModel(hephaestusRequirement)
+  }
+
+  if (!hephaestusResolution) return undefined
+  const { model: hephaestusModel, variant: hephaestusResolvedVariant } = hephaestusResolution
+
+  let hephaestusConfig = createHephaestusAgent(
+    hephaestusModel,
+    availableAgents,
+    undefined,
+    availableSkills,
+    availableCategories
+  )
+
+  hephaestusConfig = { ...hephaestusConfig, variant: hephaestusResolvedVariant ?? "medium" }
+
+  const hepOverrideCategory = (hephaestusOverride as Record<string, unknown> | undefined)?.category as string | undefined
+  if (hepOverrideCategory) {
+    hephaestusConfig = applyCategoryOverride(hephaestusConfig, hepOverrideCategory, mergedCategories)
+  }
+
+  if (directory && hephaestusConfig.prompt) {
+    const envContext = createEnvContext()
+    hephaestusConfig = { ...hephaestusConfig, prompt: hephaestusConfig.prompt + envContext }
+  }
+
+  if (hephaestusOverride) {
+    hephaestusConfig = mergeAgentConfig(hephaestusConfig, hephaestusOverride)
+  }
+  return hephaestusConfig
+}