test(KB-636): expand mission integration coverage

- Add deeper MissionStore integration tests for hierarchy integrity, rollups, reorders, and task link cleanup
- Extend mission API end-to-end coverage for feature patching, validation, and cascade scenarios
- Fix TaskStore task upsert placeholders to preserve mission slice linking fields after merge resolution
- Tidy mission CLI help text and include the published package changeset for the missions launch

packages/cli/src/bin.ts

@@ -104,7 +104,7 @@ Usage:
   fn mission create [title] [description...]  Create a new mission
   fn mission list                       List all missions
   fn mission show <id>                  Show mission with hierarchy
-  fn mission delete <id> [--force]      Delete a mission
+  fn mission delete <id> [--force]      Delete mission
   fn mission activate-slice <slice-id>  Activate a pending slice
 
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