[decompose] extract helpers from js/ui/profileModalController.js

Extracted DM Relay UI logic and DM Attachment logic into separate binder modules to reduce the size of ProfileModalController.js. Updated file size baseline.

Co-authored-by: PR0M3TH3AN <[email protected]>

test_logs/TEST_LOG_1739837127.md

@@ -0,0 +1,33 @@
+# Test Log
+
+## Environment
+- Date: 2026-02-18
+- Agent: decompose-agent
+- File: js/ui/profileModalController.js
+
+## Commands
+1. **Lint**
+   ```bash
+   npm run lint
+   ```
+   **Result:** Passed (with expected asset warnings in dev).
+
+2. **Unit Tests**
+   ```bash
+   node scripts/run-unit-tests.mjs tests/profile-modal-controller.test.mjs
+   ```
+   **Result:** Passed (18 tests).
+
+3. **File Size Check**
+   ```bash
+   node scripts/check-file-size.mjs --report
+   node scripts/check-file-size.mjs --update
+   ```
+   **Result:**
+   - Reduced `js/ui/profileModalController.js` from 6258 to 5884 lines.
+   - Updated baseline in `scripts/check-file-size.mjs`.
+
+## Manual QA
+- Verified imports in `js/ui/profileModalController.js`.
+- Verified logic in new binder files.
+- Verified no circular dependencies (binders only import utils, controller passes `this`).