refactor: onboarding, mobile nav, remove maintenance flows

- Onboarding steps guide toward copilot usage, not flow building
- Mobile nav updated to match sidebar (Session History, Guided Flows)
- Remove Step Library from mobile nav
- Remove Maintenance from flow type filter tabs
- Remove Maintenance badge from all tree views (grid, list, table)
- Remove Maintenance create option from CreateFlowDropdown
- Add copilot-first dashboard plan and solutions library spec docs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/library/TreeGridView.tsx

@@ -1,5 +1,5 @@
 import { Link } from 'react-router-dom'
-import { Pencil, Globe, Lock, Trash2, GitBranch, FileText, Wrench, Download, ClipboardList } from 'lucide-react'
+import { Pencil, Globe, Lock, Trash2, GitBranch, FileText, Download, ClipboardList } from 'lucide-react'
 import type { TreeListItem } from '@/types'
 import { TagBadges } from '@/components/common/TagBadges'
 import { StaggerList } from '@/components/common/StaggerList'
@@ -45,12 +45,6 @@ export function TreeGridView({
                   Draft
                 </span>
               )}
-              {tree.tree_type === 'maintenance' && (
-                <span className="inline-flex items-center gap-1 rounded-full border border-amber-500/30 bg-amber-500/10 px-2 py-0.5 font-sans text-xs text-[0.625rem] uppercase tracking-wide text-amber-400">
-                  <Wrench className="h-3 w-3" />
-                  Maintenance
-                </span>
-              )}
               {'fork_info' in tree && Boolean((tree as Record<string, unknown>).fork_info) && (
                 <span className="shrink-0 rounded-full bg-violet-400/15 px-1.5 py-0.5 text-[9px] font-semibold uppercase tracking-wide text-violet-400">
                   Fork

frontend/src/components/library/TreeListView.tsx

@@ -1,5 +1,5 @@
 import { Link } from 'react-router-dom'
-import { Pencil, Globe, Lock, GitBranch, FileText, Trash2, Wrench, Download, ClipboardList } from 'lucide-react'
+import { Pencil, Globe, Lock, GitBranch, FileText, Trash2, Download, ClipboardList } from 'lucide-react'
 import type { TreeListItem } from '@/types'
 import { TagBadges } from '@/components/common/TagBadges'
 import { cn } from '@/lib/utils'
@@ -45,12 +45,6 @@ export function TreeListView({
                   Draft
                 </span>
               )}
-              {tree.tree_type === 'maintenance' && (
-                <span className="inline-flex items-center gap-1 rounded-full border border-amber-500/30 bg-amber-500/10 px-2 py-0.5 font-sans text-xs text-[0.625rem] uppercase tracking-wide text-amber-400 shrink-0">
-                  <Wrench className="h-3 w-3" />
-                  Maintenance
-                </span>
-              )}
               {'fork_info' in tree && Boolean((tree as Record<string, unknown>).fork_info) && (
                 <span className="shrink-0 rounded-full bg-violet-400/15 px-1.5 py-0.5 text-[9px] font-semibold uppercase tracking-wide text-violet-400">
                   Fork

frontend/src/components/library/TreeTableView.tsx

@@ -1,6 +1,6 @@
 import { useState } from 'react'
 import { Link } from 'react-router-dom'
-import { Pencil, Globe, Lock, ChevronUp, ChevronDown, GitBranch, FileText, Trash2, Wrench, Download, ClipboardList } from 'lucide-react'
+import { Pencil, Globe, Lock, ChevronUp, ChevronDown, GitBranch, FileText, Trash2, Download, ClipboardList } from 'lucide-react'
 import type { TreeListItem } from '@/types'
 import { TagBadges } from '@/components/common/TagBadges'
 import { cn } from '@/lib/utils'
@@ -147,12 +147,6 @@ export function TreeTableView({
                       Draft
                     </span>
                   )}
-                  {tree.tree_type === 'maintenance' && (
-                    <span className="inline-flex items-center gap-1 rounded-full border border-amber-500/30 bg-amber-500/10 px-2 py-0.5 font-sans text-xs text-[0.625rem] uppercase tracking-wide text-amber-400 shrink-0">
-                      <Wrench className="h-3 w-3" />
-                      Maintenance
-                    </span>
-                  )}
                   {'fork_info' in tree && Boolean((tree as Record<string, unknown>).fork_info) && (
                     <span className="shrink-0 rounded-full bg-violet-400/15 px-1.5 py-0.5 text-[9px] font-semibold uppercase tracking-wide text-violet-400">
                       Fork