fix(tasks): guard loop name length and surface loop ownership in the UI

Review follow-up:

- Reject loop files whose frontmatter name exceeds MAX_TASK_NAME_LENGTH
  (80): task names are clamped at storage time, so a raw name longer than
  the limit could never match the stored task identity. The file is treated
  as malformed (definition: null) instead of creating an unreachable
  definition; MAX_TASK_NAME_LENGTH is now exported from project-config.js
  and shared with loops.js.
- Surface loop-sourced tasks in the scheduled-tasks dialog: tasks carrying
  loopFile show a 'Managed by loop file <path>' note, and the enable
  toggle / edit / delete actions are disabled with an explanatory tooltip,
  since the file remains authoritative and would revert any such change.
  run-now stays available. New locale keys added to all 11 message files
  (i18n parity test enforces exact key sets).
- ScheduledTask type gains an optional loopFile field (additive, unknown
  to older clients).

packages/web/server/lib/scheduled-tasks/loops.js

@@ -41,6 +41,7 @@ import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import { parseMdFile, getAncestors, findWorktreeRoot } from '../opencode/shared.js';
+import { MAX_TASK_NAME_LENGTH } from '../projects/project-config.js';
 
 const LOOP_DIR_NAME = 'loops';
 const USER_LOOP_ROOT = () => path.join(os.homedir(), '.agents', LOOP_DIR_NAME);
@@ -94,6 +95,12 @@ export const parseLoopDefinition = (filePath) => {
     console.warn(`[loops] skipped ${filePath}: frontmatter "name" is required`);
     return null;
   }
+  if (name.length > MAX_TASK_NAME_LENGTH) {
+    // Reject instead of clamping: task names are clamped to this length at
+    // storage time, so identity keys must match the stored value exactly.
+    console.warn(`[loops] skipped ${filePath}: frontmatter "name" exceeds ${MAX_TASK_NAME_LENGTH} characters`);
+    return null;
+  }
 
   const cron = asNonEmptyString(frontmatter.schedule);
   if (!cron) {