apps/ui: Unify url usage

[nightnei]

How AI was used in this PR

AI assisted

Proposed Changes

Let's clean up URLs usage in apps/ui

Testing Instructions

Visual review shoudl suffice, but JIC:

1. npm run cli:build && npm start
2. Electron -> Feature flags -> Enable agentic UI
3. Click on Documentation and Report an issue
   
4. Assert that you are landed on the correct URLs
5. Switch language to Spanish
6. Click again and assert that Documentation leads to the Spanish version
7. Open Studio Settings and repeat the same steps with these two buttons:
   
8. Open drop down menu here -> Click on Publish -> Click on Create a new wordpress.com site... and assert taht you are landed to https://wordpress.com/setup/new-hosted-site/domains.....
   
   8 Repeat the 8-th step via browser:

npm run cli:build
node apps/cli/dist/cli/main.mjs ui --port 8081 --no-open
npm run dev:local --workspace=apps/ui
# Open http://localhost:5400

[bcotrim]

LGTM 👍

Approving so we can merge once we address the studio1 comment, or confirm it is intentional

[wpmobilebot]

📊 Performance Test Results

Comparing f0ae4c7 vs trunk

app-size

Metric	trunk	f0ae4c7	Diff	Change
App Size (Mac)	1361.88 MB	1361.88 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	f0ae4c7	Diff	Change
load	1082 ms	1112 ms	+30 ms	⚪ 0.0%

site-startup

Metric	trunk	f0ae4c7	Diff	Change
siteCreation	7029 ms	6999 ms	30 ms	⚪ 0.0%
siteStartup	2355 ms	2364 ms	+9 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)