feat(addons): ship Studio and Talk as add-ons instead of built-in pages

Studio and Talk were compiled into the web bundle and always listed in
the Add-ons drawer. They are add-ons now, like Voice, Face, fine-tuning
and quantization: a person installs and removes them, the drawer lists
them only while they are installed, and they are packaged the same way.

Move the pages, their components, hooks and helpers into addons/studio
and addons/talk. Each has a manifest, a UI bundle, a release platform
matrix and a catalog template, and is built by the compat mode of the
shared builder. The core API stays where it is: the pages call it with
the signed-in person's session. The history keeps its browser storage
keys. The unit tests of the moved helpers move with them.

In the core, drop the two pages, the Create group of the sidebar (Chat
joins Home and Models in the old layout), the built-in catalog entries
(the catalog is empty) and the talk locale namespace. The old addresses
(/app/studio, /app/talk and the generator links) redirect to the add-on
pages, with the model as ?model=. The Home /studio command is offered
only while the Studio add-on is installed and opens it.

The release workflow and its tests now list seven add-ons.

Assisted-by: Claude Code:claude-sonnet-5-5 go node
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

.github/workflows/addons-package.yml

@@ -56,7 +56,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        addon: [tables, voice, face, fine-tuning, quantization]
+        addon: [tables, voice, face, fine-tuning, quantization, studio, talk]
     steps:
       - uses: actions/checkout@v7
         with:
@@ -155,7 +155,7 @@ jobs:
           # event it fails the plan. A missing or malformed platform file, or
           # any other error, fails the plan on every event.
           include='[]'
-          for id in tables voice face fine-tuning quantization; do
+          for id in tables voice face fine-tuning quantization studio talk; do
             cfg="addons/$id/package/platforms.yaml"
             err="matrix-$id.err"
             if rows=$(go run ./scripts/addons/cmd/addonpkg matrix --config "$cfg" 2>"$err"); then