feat(hooks): add HTTP hook handler support

Add type: "http" hook support matching Claude Code's HTTP hook specification.
HTTP hooks send POST requests with JSON body, support env var interpolation
in headers via allowedEnvVars, and configurable timeout.

New files:
- execute-http-hook.ts: HTTP hook execution with env var interpolation
- dispatch-hook.ts: Unified dispatcher for command and HTTP hooks
- execute-http-hook.test.ts: 14 tests covering all HTTP hook scenarios

Modified files:
- types.ts: Added HookHttp interface, HookAction union type
- config.ts: Updated to accept HookAction in raw hook matchers
- pre-tool-use/post-tool-use/stop/user-prompt-submit/pre-compact:
  Updated all 5 executors to dispatch HTTP hooks via dispatchHook()
- plugin-loader/types.ts: Added "http" to HookEntry type union

src/hooks/claude-code-hooks/dispatch-hook.ts

@@ -0,0 +1,27 @@
+import type { HookAction } from "./types"
+import type { CommandResult } from "../../shared/command-executor/execute-hook-command"
+import { executeHookCommand } from "../../shared"
+import { executeHttpHook } from "./execute-http-hook"
+import { DEFAULT_CONFIG } from "./plugin-config"
+
+export function getHookIdentifier(hook: HookAction): string {
+  if (hook.type === "http") return hook.url
+  return hook.command.split("/").pop() || hook.command
+}
+
+export async function dispatchHook(
+  hook: HookAction,
+  stdinJson: string,
+  cwd: string
+): Promise<CommandResult> {
+  if (hook.type === "http") {
+    return executeHttpHook(hook, stdinJson)
+  }
+
+  return executeHookCommand(
+    hook.command,
+    stdinJson,
+    cwd,
+    { forceZsh: DEFAULT_CONFIG.forceZsh, zshPath: DEFAULT_CONFIG.zshPath }
+  )
+}