feat(hooks): add hashline-edit-diff-enhancer for TUI inline diff display

Capture file content before hashline edit execution and compute filediff
metadata after, enabling opencode TUI to render inline diffs for the
plugin's edit tool (which replaces the built-in EditTool).

src/plugin/tool-execute-before.ts

@@ -29,6 +29,7 @@ export function createToolExecuteBeforeHandler(args: {
     await hooks.prometheusMdOnly?.["tool.execute.before"]?.(input, output)
     await hooks.sisyphusJuniorNotepad?.["tool.execute.before"]?.(input, output)
     await hooks.atlasHook?.["tool.execute.before"]?.(input, output)
+    await hooks.hashlineEditDiffEnhancer?.["tool.execute.before"]?.(input, output)
     if (input.tool === "task") {
       const argsObject = output.args
       const category = typeof argsObject.category === "string" ? argsObject.category : undefined