Add a Publisher abstraction and queued job to publish from the UI

Introduce Publisher/PublisherManager (WordPress + Reddit implementations)
so publishing logic is shared between the CLI, the queue, and future
network integrations. Add a "Publish" button on the Posts page that
dispatches PublishPostJob instead of blocking the request — Reddit's
publisher shells out to the existing Playwright sidecar and can take
tens of seconds, so it can't run synchronously in a web request.

Adds a `target` field (e.g. subreddit) and `publishing` status to Post,
plus a `publish_error` field so failures surface in the UI. Refactors
posts:publish to delegate to WordPressPublisher without changing its
CLI output contract (existing tests pass unchanged).

Also fixes two bugs found along the way: UpdatePostRequest was silently
dropping `published_url` from PATCH requests (never in its validation
rules, despite AI_API.md documenting it), and three Livewire index-page
tests were broken by the earlier auth change (never re-run after adding
the `auth` middleware) since they hit routes via HTTP without a logged-in
user.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -15,17 +15,23 @@ Built with Laravel 13, Livewire, and Tailwind CSS.
 - **Social Accounts** — logins for social networks (Twitter, Instagram,
   Facebook, Reddit, TikTok, LinkedIn, YouTube, etc.).
 - **Posts** — the actual content, each tied to a Site and optionally a
-  Social Account, moving through `draft -> scheduled -> published/failed`.
+  Social Account, moving through
+  `draft -> scheduled -> publishing -> published/failed`.
 - A **JSON API** (`/api/sites`, `/api/accounts`, `/api/posts`) plus thin
   Python CLI wrappers in `python_scripts/`, so an agent can poll for due
   posts (`?due=1`) and drive the publish lifecycle without hand-rolling
   HTTP requests.
-- Built-in publishing paths:
-  - **WordPress**: `php artisan posts:publish {post_id}` posts directly to
-    a site's WordPress REST API and updates the post's status.
-  - **Reddit**: a standalone Playwright sidecar at
-    `sidecars/reddit-post/` logs in and creates a post.
-  - Anything else: publish however fits, then report back via the API.
+- A **Publish button** in the UI (Posts page) for any post whose network has
+  a publisher wired up — queues a background job so slow, flaky publishers
+  (e.g. Reddit's browser automation) don't block the page.
+- Built-in publishers (`app/Support/Publishing/`), one per network, resolved
+  by `Post.type`:
+  - **WordPress**: posts directly to a site's WordPress REST API. Also
+    available synchronously from the CLI: `php artisan posts:publish {post_id}`.
+  - **Reddit**: drives a standalone Playwright sidecar at
+    `sidecars/reddit-post/` that logs in and creates a post.
+  - Anything else: no publisher yet — publish however fits, then report
+    back via the API.
 
 See `AI_API.md` for the full API reference and publishing contract, and
 `python_scripts/README.md` for the CLI wrapper usage.
@@ -80,6 +86,14 @@ This starts the PHP dev server, queue listener, log viewer (Pail), and
 Vite dev server together. The app is served at `http://localhost:8000` by
 default.
 
+Outside of `composer run dev` (e.g. a plain production deploy), the Publish
+button needs its own queue worker running, or queued publishes will just sit
+in the `jobs` table:
+
+```bash
+php artisan queue:work
+```
+
 ### Reddit sidecar (optional)
 
 If you plan to publish to Reddit, set up the Playwright sidecar separately: