feat: forum rich-text editor, emoji picker, mentions, discover nav, feed, uploads, profile

Forum:
- TipTap WYSIWYG editor with full toolbar
- @emoji-mart/react emoji picker (consistent with tweets)
- @mention autocomplete with user search API
- Fix PHP 8.4 parse errors in Blade templates
- Fix thread data display (paginator items)
- Align forum page widths to max-w-5xl

Discover:
- Extract shared _nav.blade.php partial
- Add missing nav links to for-you page
- Add Following link for authenticated users

Feed/Posts:
- Post model, controllers, policies, migrations
- Feed page components (PostComposer, FeedCard, etc)
- Post reactions, comments, saves, reports, sharing
- Scheduled publishing support
- Link preview controller

Profile:
- Profile page components (ProfileHero, ProfileTabs)
- Profile API controller

Uploads:
- Upload wizard enhancements
- Scheduled publish picker
- Studio status bar and readiness checklist

resources/js/Pages/Forum/ForumNewThread.jsx

@@ -0,0 +1,91 @@
+import React, { useState, useCallback } from 'react'
+import Breadcrumbs from '../../components/forum/Breadcrumbs'
+import Button from '../../components/ui/Button'
+import TextInput from '../../components/ui/TextInput'
+import RichTextEditor from '../../components/forum/RichTextEditor'
+
+export default function ForumNewThread({ category, csrfToken, errors = {}, oldValues = {} }) {
+  const [title, setTitle]     = useState(oldValues.title ?? '')
+  const [content, setContent] = useState(oldValues.content ?? '')
+  const [submitting, setSubmitting] = useState(false)
+
+  const slug = category?.slug
+  const categoryName = category?.name ?? 'Category'
+
+  const breadcrumbs = [
+    { label: 'Home', href: '/' },
+    { label: 'Forum', href: '/forum' },
+    { label: categoryName, href: slug ? `/forum/${slug}` : '/forum' },
+    { label: 'New thread' },
+  ]
+
+  const handleSubmit = useCallback(async (e) => {
+    e.preventDefault()
+    if (submitting) return
+    setSubmitting(true)
+
+    // Standard form submission to keep server-side validation + redirect
+    e.target.submit()
+  }, [submitting])
+
+  return (
+    <div className="px-4 pt-10 pb-20 sm:px-6 lg:px-8 max-w-3xl mx-auto">
+      <Breadcrumbs items={breadcrumbs} />
+
+      {/* Header */}
+      <div className="mt-5 mb-6">
+        <p className="text-xs font-semibold uppercase tracking-widest text-white/30 mb-1">New thread</p>
+        <h1 className="text-2xl font-bold text-white leading-tight">
+          Create thread in {categoryName}
+        </h1>
+      </div>
+
+      {/* Form */}
+      <form
+        method="POST"
+        action={`/forum/${slug}/new`}
+        onSubmit={handleSubmit}
+        className="space-y-5 rounded-2xl border border-white/[0.06] bg-nova-800/50 p-6 backdrop-blur"
+      >
+        <input type="hidden" name="_token" value={csrfToken} />
+
+        <TextInput
+          label="Title"
+          name="title"
+          value={title}
+          onChange={(e) => setTitle(e.target.value)}
+          required
+          maxLength={255}
+          placeholder="Thread title…"
+          error={errors.title}
+        />
+
+        {/* Rich text editor */}
+        <div>
+          <label className="mb-1.5 block text-sm font-medium text-white/85">
+            Content <span className="text-red-400 ml-1">*</span>
+          </label>
+          <RichTextEditor
+            content={content}
+            onChange={setContent}
+            placeholder="Write your post…"
+            error={errors.content}
+            minHeight={14}
+            autofocus={false}
+          />
+          <input type="hidden" name="content" value={content} />
+        </div>
+
+        {/* Submit */}
+        <div className="flex items-center justify-between pt-2">
+          <a href={`/forum/${slug}`} className="text-sm text-zinc-500 hover:text-zinc-300 transition-colors">
+            ← Cancel
+          </a>
+          <Button type="submit" variant="primary" size="md" loading={submitting}>
+            Publish thread
+          </Button>
+        </div>
+      </form>
+    </div>
+  )
+}