feat(settings): unified settings modal with context switcher (Phase 1)

New unified settings modal accessible via `,` keyboard shortcut.
Three-context switcher: Site (with site dropdown), Workspace, Account.
Horizontal tabs per context with animated transitions.

Phase 1 tabs implemented:
- Site → General (name, timezone, domain, tracking script with copy)
- Site → Goals (CRUD with inline create/edit)
- Workspace → General (org name, slug, danger zone)
- Workspace → Billing (plan card, usage, cancel/resume, portal)
- Account → Profile (wraps existing ProfileSettings)

Phase 2 tabs show "Coming soon" placeholder:
- Site: Visibility, Privacy, Bot & Spam, Reports, Integrations
- Workspace: Members, Notifications, Audit Log
- Account: Security, Devices

Old settings pages and profile modal remain functional.

components/settings/unified/tabs/WorkspaceGeneralTab.tsx

@@ -0,0 +1,98 @@
+'use client'
+
+import { useState, useEffect } from 'react'
+import { Input, Button, toast } from '@ciphera-net/ui'
+import { Spinner } from '@ciphera-net/ui'
+import { useAuth } from '@/lib/auth/context'
+import { getOrganization, updateOrganization } from '@/lib/api/organization'
+import { getAuthErrorMessage } from '@ciphera-net/ui'
+
+export default function WorkspaceGeneralTab() {
+  const { user } = useAuth()
+  const [name, setName] = useState('')
+  const [slug, setSlug] = useState('')
+  const [loading, setLoading] = useState(true)
+  const [saving, setSaving] = useState(false)
+
+  useEffect(() => {
+    if (!user?.org_id) return
+    setLoading(true)
+    getOrganization(user.org_id)
+      .then(org => {
+        setName(org.name || '')
+        setSlug(org.slug || '')
+      })
+      .catch(() => {})
+      .finally(() => setLoading(false))
+  }, [user?.org_id])
+
+  const handleSave = async () => {
+    if (!user?.org_id) return
+    setSaving(true)
+    try {
+      await updateOrganization(user.org_id, name, slug)
+      toast.success('Workspace updated')
+    } catch (err) {
+      toast.error(getAuthErrorMessage(err as Error) || 'Failed to update workspace')
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  if (loading) {
+    return (
+      <div className="flex items-center justify-center py-12">
+        <Spinner className="w-6 h-6 text-neutral-500" />
+      </div>
+    )
+  }
+
+  return (
+    <div className="space-y-8">
+      <div className="space-y-4">
+        <div>
+          <h3 className="text-base font-semibold text-white mb-1">General Information</h3>
+          <p className="text-sm text-neutral-400">Basic details about your workspace.</p>
+        </div>
+
+        <div>
+          <label className="block text-sm font-medium text-neutral-300 mb-1.5">Organization Name</label>
+          <Input value={name} onChange={e => setName(e.target.value)} placeholder="Acme Corp" />
+        </div>
+
+        <div>
+          <label className="block text-sm font-medium text-neutral-300 mb-1.5">Organization Slug</label>
+          <div className="flex items-center gap-2">
+            <span className="text-sm text-neutral-500">pulse.ciphera.net/</span>
+            <Input value={slug} onChange={e => setSlug(e.target.value)} placeholder="acme-corp" />
+          </div>
+          <p className="text-xs text-neutral-500 mt-1">Changing the slug will change your organization's URL.</p>
+        </div>
+      </div>
+
+      <div className="flex justify-end">
+        <Button onClick={handleSave} variant="primary" disabled={saving}>
+          {saving ? 'Saving...' : 'Save Changes'}
+        </Button>
+      </div>
+
+      {/* Danger Zone */}
+      <div className="space-y-3 pt-4 border-t border-neutral-800">
+        <h3 className="text-base font-semibold text-red-500">Danger Zone</h3>
+        <div className="flex items-center justify-between rounded-xl border border-red-900/30 bg-red-900/10 p-4">
+          <div>
+            <p className="text-sm font-medium text-white">Delete Organization</p>
+            <p className="text-xs text-neutral-400">Permanently delete this organization and all its data.</p>
+          </div>
+          <Button
+            variant="secondary"
+            className="text-red-400 border-red-900 hover:bg-red-900/20 text-sm"
+            onClick={() => toast.error('Use Organization Settings page for destructive actions')}
+          >
+            Delete
+          </Button>
+        </div>
+      </div>
+    </div>
+  )
+}