refactor!: rebrand bterminal to agor (agents-orchestrator)

Rename Cargo crates (bterminal-core→agor-core, bterminal-relay→agor-relay),
env vars (BTERMINAL_*→AGOR_*), config paths (~/.config/agor), CSS custom
properties, plugin API object, package names, and all documentation.

BREAKING CHANGE: config/data paths changed from bterminal to agor.

.github/workflows/release.yml

@@ -85,7 +85,7 @@ jobs:
             "platforms": {
               "linux-x86_64": {
                 "signature": "${SIG}",
-                "url": "https://github.com/DexterFromLab/BTerminal/releases/download/${GITHUB_REF_NAME}/${APPIMAGE_NAME}"
+                "url": "https://github.com/agents-orchestrator/agents-orchestrator/releases/download/${GITHUB_REF_NAME}/${APPIMAGE_NAME}"
               }
             }
           }
@@ -94,13 +94,13 @@ jobs:
       - name: Upload .deb
         uses: actions/upload-artifact@v4
         with:
-          name: bterminal-deb
+          name: agor-deb
           path: v2/src-tauri/target/release/bundle/deb/*.deb
 
       - name: Upload AppImage
         uses: actions/upload-artifact@v4
         with:
-          name: bterminal-appimage
+          name: agor-appimage
           path: v2/src-tauri/target/release/bundle/appimage/*.AppImage
 
       - name: Upload latest.json
@@ -118,13 +118,13 @@ jobs:
       - name: Download .deb
         uses: actions/download-artifact@v4
         with:
-          name: bterminal-deb
+          name: agor-deb
           path: artifacts/
 
       - name: Download AppImage
         uses: actions/download-artifact@v4
         with:
-          name: bterminal-appimage
+          name: agor-appimage
           path: artifacts/
 
       - name: Download latest.json