feat: Use self-hosted runner for E2E tests

- Changed from GitHub-hosted runners to self-hosted Linux runner
- Removed Windows job (using Linux VM with desktop for WebKitGTK)
- Added disk cleanup steps to save space
- Added cargo/rust env sourcing for tauri-driver
- Runner labels: self-hosted, linux, lokus-e2e

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: CodeWithInferno

.github/workflows/e2e-tests-new.yml

@@ -43,12 +43,16 @@ jobs:
         run: npm run bundle:mcp && npm run build
 
       - name: Build Tauri binary (debug, no bundling)
-        run: cargo build --manifest-path src-tauri/Cargo.toml
+        run: |
+          source $HOME/.cargo/env
+          cargo build --manifest-path src-tauri/Cargo.toml
         env:
           TAURI_SIGNING_PRIVATE_KEY: ''
 
       - name: Run Tauri E2E tests
-        run: xvfb-run --auto-servernum npm run test:e2e:tauri
+        run: |
+          source $HOME/.cargo/env
+          xvfb-run --auto-servernum npm run test:e2e:tauri
         env:
           CI: 'true'
           TAURI_BINARY: ./src-tauri/target/debug/lokus