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/components/forum/EmojiPicker.jsx

@@ -0,0 +1,111 @@
+import React, { useState, useRef, useEffect, useCallback } from 'react'
+import { createPortal } from 'react-dom'
+import data from '@emoji-mart/data'
+import Picker from '@emoji-mart/react'
+
+/**
+ * Emoji picker button for the forum rich-text editor.
+ * Uses the same @emoji-mart/react picker as profile tweets / comments
+ * so the UI is consistent across the whole site.
+ *
+ * The panel is rendered through a React portal so it escapes any
+ * overflow-hidden containers (like the editor wrapper).
+ */
+export default function EmojiPicker({ onSelect, editor }) {
+  const [open, setOpen] = useState(false)
+  const [panelStyle, setPanelStyle] = useState({})
+  const panelRef = useRef(null)
+  const buttonRef = useRef(null)
+
+  // Position the portal panel relative to the trigger button
+  useEffect(() => {
+    if (!open || !buttonRef.current) return
+    const rect = buttonRef.current.getBoundingClientRect()
+    const panelWidth = 352   // emoji-mart default width
+    const panelHeight = 435  // approximate picker height
+
+    const spaceAbove = rect.top
+    const openAbove = spaceAbove > panelHeight + 8
+
+    setPanelStyle({
+      position: 'fixed',
+      zIndex: 9999,
+      left: Math.max(8, Math.min(rect.right - panelWidth, window.innerWidth - panelWidth - 8)),
+      ...(openAbove
+        ? { bottom: window.innerHeight - rect.top + 6 }
+        : { top: rect.bottom + 6 }),
+    })
+  }, [open])
+
+  // Close on outside click
+  useEffect(() => {
+    if (!open) return
+    const handler = (e) => {
+      if (panelRef.current && !panelRef.current.contains(e.target) &&
+          buttonRef.current && !buttonRef.current.contains(e.target)) {
+        setOpen(false)
+      }
+    }
+    document.addEventListener('mousedown', handler)
+    return () => document.removeEventListener('mousedown', handler)
+  }, [open])
+
+  // Close on Escape
+  useEffect(() => {
+    if (!open) return
+    const handler = (e) => { if (e.key === 'Escape') setOpen(false) }
+    document.addEventListener('keydown', handler)
+    return () => document.removeEventListener('keydown', handler)
+  }, [open])
+
+  const handleSelect = useCallback((emoji) => {
+    const native = emoji.native ?? ''
+    onSelect?.(native)
+    if (editor) {
+      editor.chain().focus().insertContent(native).run()
+    }
+    setOpen(false)
+  }, [onSelect, editor])
+
+  const panel = open ? createPortal(
+    <div
+      ref={panelRef}
+      style={panelStyle}
+      className="rounded-xl shadow-2xl overflow-hidden"
+    >
+      <Picker
+        data={data}
+        onEmojiSelect={handleSelect}
+        theme="dark"
+        previewPosition="none"
+        skinTonePosition="search"
+        maxFrequentRows={2}
+        perLine={9}
+      />
+    </div>,
+    document.body,
+  ) : null
+
+  return (
+    <div className="relative">
+      <button
+        ref={buttonRef}
+        type="button"
+        onClick={() => setOpen((v) => !v)}
+        title="Insert emoji"
+        aria-label="Open emoji picker"
+        aria-expanded={open}
+        className={[
+          'inline-flex h-8 w-8 items-center justify-center rounded-lg text-sm transition-colors',
+          'focus:outline-none focus-visible:ring-2 focus-visible:ring-sky-400',
+          open
+            ? 'bg-sky-600/25 text-sky-300'
+            : 'text-zinc-400 hover:bg-white/[0.06] hover:text-zinc-200',
+        ].join(' ')}
+      >
+        <span className="text-[15px]">😊</span>
+      </button>
+      {panel}
+    </div>
+  )
+}