fix: app -> this.app

[GennoBou]

Description

Fixed TypeScript build errors caused by incorrect references to app instead of this.app in src/arrange.ts.
The build previously failed with the following errors:
I can only speak Japanese, so I translate it into English.

> pnpm run build

> obsidian-attachment-management@0.9.16 build D:\Data\obsidian-attachment-management
> tsc -noEmit -skipLibCheck && cross-env BUILD_ENV=production node esbuild.config.mjs

src/arrange.ts:259:81 - error TS2663: Cannot find name 'app'. Did you mean the instance member 'this.app'?

259         const linkMatches: LinkMatch[] = await getAllLinkMatchesInFile(obsFile, app);
                                                                                    ~~~

src/arrange.ts:287:87 - error TS2663: Cannot find name 'app'. Did you mean the instance member 'this.app'?

287               const linkMatches: LinkMatch[] = await getAllLinkMatchesInFile(obsFile, app, node.text);
                                                                                          ~~~


Found 2 errors in the same file, starting at: src/arrange.ts:259

 ELIFECYCLE  Command failed with exit code 2.

Changes

Replaced app with this.app in two locations within arrange.ts

Verified that the project now builds successfully with pnpm run build

Result

✅ TypeScript build passes without errors.