fix(ci): install Tauri system dependencies in nightly containers

Fix for dbus-1 and webkit build errors:
'Package dbus-1 was not found in the pkg-config search path'

**Problem:**
rustlang/rust:nightly is a minimal image with only rustc/cargo.
Tauri requires system libraries: webkit2gtk, dbus, gtk, ssl, etc.
Without these, cargo build fails with missing pkg-config packages.

**Solution:**
Added system dependency installation step to all Rust jobs:
- libwebkit2gtk-4.1-dev (WebView)
- libdbus-1-dev (D-Bus IPC)
- libgtk-3-dev (GTK UI)
- libayatana-appindicator3-dev (System tray)
- librsvg2-dev (SVG rendering)
- libssl-dev (OpenSSL)
- pkg-config (Build tool)

**Changed Jobs:**
- rust-fmt-check: Added system deps before rustfmt
- rust-clippy: Added system deps before clippy
- rust-tests: Added system deps before tests

**Why Each Job Needs Deps:**
All jobs run 'cargo' commands which trigger dependency builds.
Even 'cargo fmt' can trigger builds if dependencies aren't cached.
System libraries must be present for Tauri crates to compile.

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

.gitea/workflows/test.yml

@@ -35,6 +35,16 @@ jobs:
           apt-get update && apt-get install -y curl
           curl -fsSL https://deb.nodesource.com/setup_22.x | bash -
           apt-get install -y nodejs
+      - name: Install system dependencies
+        run: |
+          apt-get update && apt-get install -y \
+            libwebkit2gtk-4.1-dev \
+            libssl-dev \
+            libgtk-3-dev \
+            libayatana-appindicator3-dev \
+            librsvg2-dev \
+            libdbus-1-dev \
+            pkg-config
       - name: Install Rust components
         run: rustup component add rustfmt
       - name: Install dependencies
@@ -67,6 +77,16 @@ jobs:
             echo "Fetched fallback ref: master"
           fi
           git checkout FETCH_HEAD
+      - name: Install system dependencies
+        run: |
+          apt-get update && apt-get install -y \
+            libwebkit2gtk-4.1-dev \
+            libssl-dev \
+            libgtk-3-dev \
+            libayatana-appindicator3-dev \
+            librsvg2-dev \
+            libdbus-1-dev \
+            pkg-config
       - name: Install clippy
         run: rustup component add clippy
       - run: cargo clippy --manifest-path src-tauri/Cargo.toml -- -D warnings
@@ -94,6 +114,16 @@ jobs:
             echo "Fetched fallback ref: master"
           fi
           git checkout FETCH_HEAD
+      - name: Install system dependencies
+        run: |
+          apt-get update && apt-get install -y \
+            libwebkit2gtk-4.1-dev \
+            libssl-dev \
+            libgtk-3-dev \
+            libayatana-appindicator3-dev \
+            librsvg2-dev \
+            libdbus-1-dev \
+            pkg-config
       - run: cargo test --manifest-path src-tauri/Cargo.toml -- --test-threads=1
 
       - name: Run shell module tests