fix(ci): exclude wraith-transfer from documentation workflow

The documentation workflow was failing because it tried to build docs
for wraith-transfer, a Tauri-based desktop application with GTK
dependencies (glib-sys) that aren't installed in the CI environment.

Changes:
- Add --exclude wraith-transfer to cargo doc commands (lines 114, 122)
- Consistent with other workflows (ci.yml, codeql.yml, release.yml)

Fixes:
- glib-sys build failure in docs.yml workflow
- Documentation build now succeeds without system dependencies

Tested locally:
- RUSTDOCFLAGS="-Dwarnings" cargo doc --workspace --no-deps --exclude wraith-transfer
- Completed in 4.78s with no errors

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: doublegate

.github/workflows/docs.yml

@@ -111,15 +111,15 @@ jobs:
             ${{ runner.os }}-cargo-
 
       - name: Build documentation
-        run: cargo doc --workspace --no-deps
+        run: cargo doc --workspace --no-deps --exclude wraith-transfer
         env:
           RUSTDOCFLAGS: -Dwarnings
 
       - name: Check for missing documentation
         run: |
           # Count documented vs undocumented items
           echo "Checking documentation coverage..."
-          cargo doc --workspace --no-deps 2>&1 | grep -c "warning: missing documentation" || echo "0 missing documentation warnings"
+          cargo doc --workspace --no-deps --exclude wraith-transfer 2>&1 | grep -c "warning: missing documentation" || echo "0 missing documentation warnings"
 
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