Consolidate duplicate patterns and simplify codebase (#1317)

* refactor(shared): unify binary downloader and session path storage

- Create binary-downloader.ts for common download/extract logic
- Create session-injected-paths.ts for unified path tracking
- Refactor comment-checker, ast-grep, grep downloaders to use shared util
- Consolidate directory injector types into shared module

* feat(shared): implement unified model resolution pipeline

- Create ModelResolutionPipeline for centralized model selection
- Refactor model-resolver to use pipeline
- Update delegate-task and config-handler to use unified logic
- Ensure consistent model resolution across all agent types

* refactor(agents): simplify agent utils and metadata management

- Extract helper functions for config merging and env context
- Register prompt metadata for all agents
- Simplify agent variant detection logic

* cleanup: inline utilities and remove unused exports

- Remove case-insensitive.ts (inline with native JS)
- Simplify opencode-version helpers
- Remove unused getModelLimit, createCompactionContextInjector exports
- Inline transcript entry creation in claude-code-hooks
- Update tests accordingly

---------

Co-authored-by: justsisyphus <justsisyphus@users.noreply.github.com>

src/hooks/session-notification-utils.ts

@@ -2,24 +2,6 @@ import { spawn } from "bun"
 
 type Platform = "darwin" | "linux" | "win32" | "unsupported"
 
-let notifySendPath: string | null = null
-let notifySendPromise: Promise<string | null> | null = null
-
-let osascriptPath: string | null = null
-let osascriptPromise: Promise<string | null> | null = null
-
-let powershellPath: string | null = null
-let powershellPromise: Promise<string | null> | null = null
-
-let afplayPath: string | null = null
-let afplayPromise: Promise<string | null> | null = null
-
-let paplayPath: string | null = null
-let paplayPromise: Promise<string | null> | null = null
-
-let aplayPath: string | null = null
-let aplayPromise: Promise<string | null> | null = null
-
 async function findCommand(commandName: string): Promise<string | null> {
   const isWindows = process.platform === "win32"
   const cmd = isWindows ? "where" : "which"
@@ -48,83 +30,30 @@ async function findCommand(commandName: string): Promise<string | null> {
   }
 }
 
-export async function getNotifySendPath(): Promise<string | null> {
-  if (notifySendPath !== null) return notifySendPath
-  if (notifySendPromise) return notifySendPromise
+function createCommandFinder(commandName: string): () => Promise<string | null> {
+  let cachedPath: string | null = null
+  let pending: Promise<string | null> | null = null
 
-  notifySendPromise = (async () => {
-    const path = await findCommand("notify-send")
-    notifySendPath = path
-    return path
-  })()
+  return async () => {
+    if (cachedPath !== null) return cachedPath
+    if (pending) return pending
 
-  return notifySendPromise
+    pending = (async () => {
+      const path = await findCommand(commandName)
+      cachedPath = path
+      return path
+    })()
+
+    return pending
+  }
 }
 
-export async function getOsascriptPath(): Promise<string | null> {
-  if (osascriptPath !== null) return osascriptPath
-  if (osascriptPromise) return osascriptPromise
-
-  osascriptPromise = (async () => {
-    const path = await findCommand("osascript")
-    osascriptPath = path
-    return path
-  })()
-
-  return osascriptPromise
-}
-
-export async function getPowershellPath(): Promise<string | null> {
-  if (powershellPath !== null) return powershellPath
-  if (powershellPromise) return powershellPromise
-
-  powershellPromise = (async () => {
-    const path = await findCommand("powershell")
-    powershellPath = path
-    return path
-  })()
-
-  return powershellPromise
-}
-
-export async function getAfplayPath(): Promise<string | null> {
-  if (afplayPath !== null) return afplayPath
-  if (afplayPromise) return afplayPromise
-
-  afplayPromise = (async () => {
-    const path = await findCommand("afplay")
-    afplayPath = path
-    return path
-  })()
-
-  return afplayPromise
-}
-
-export async function getPaplayPath(): Promise<string | null> {
-  if (paplayPath !== null) return paplayPath
-  if (paplayPromise) return paplayPromise
-
-  paplayPromise = (async () => {
-    const path = await findCommand("paplay")
-    paplayPath = path
-    return path
-  })()
-
-  return paplayPromise
-}
-
-export async function getAplayPath(): Promise<string | null> {
-  if (aplayPath !== null) return aplayPath
-  if (aplayPromise) return aplayPromise
-
-  aplayPromise = (async () => {
-    const path = await findCommand("aplay")
-    aplayPath = path
-    return path
-  })()
-
-  return aplayPromise
-}
+export const getNotifySendPath = createCommandFinder("notify-send")
+export const getOsascriptPath = createCommandFinder("osascript")
+export const getPowershellPath = createCommandFinder("powershell")
+export const getAfplayPath = createCommandFinder("afplay")
+export const getPaplayPath = createCommandFinder("paplay")
+export const getAplayPath = createCommandFinder("aplay")
 
 export function startBackgroundCheck(platform: Platform): void {
   if (platform === "darwin") {