feat(frontend): Add Templates page for managing contract templates

- Add NavStrip component for top navigation between pages
- Create Templates page with template card grid layout
- Create TemplateEditor component for editing phase deliverables
- Add navigation state management in stores
- Implement three built-in templates:
  - Simple: Plan phase (Plan deliverable), Execute phase (PR deliverable)
  - Specification: Research, Specify, Plan, Execute, Review phases with deliverables
  - Execute: Single execute phase with no deliverables
- Support for creating custom templates with configurable phases/deliverables
- Templates are persisted to localStorage
- Add comprehensive CSS styling matching existing design patterns

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

[WIP] Heartbeat checkpoint - 2026-01-24 16:13:00 UTC

[WIP] Heartbeat checkpoint - 2026-01-24 16:14:29 UTC

3 files changed, 252 insertions, 3 deletions

diff --git a/frontend/src/components/NavStrip.tsx b/frontend/src/components/NavStrip.tsx
new file mode 100644
index 0000000..c0fc000
--- /dev/null
+++ b/frontend/src/components/NavStrip.tsx
@@ -0,0 +1,30 @@
+import React from 'react'
+
+type NavItem = {
+  id: string
+  label: string
+  icon?: string
+}
+
+type Props = {
+  items: NavItem[]
+  activeId: string
+  onSelect: (id: string) => void
+}
+
+export const NavStrip: React.FC<Props> = ({ items, activeId, onSelect }) => {
+  return (
+    <nav className="nav-strip">
+      {items.map((item) => (
+        <button
+          key={item.id}
+          className={`nav-strip-item ${activeId === item.id ? 'active' : ''}`}
+          onClick={() => onSelect(item.id)}
+        >
+          {item.icon && <span className="nav-icon">{item.icon}</span>}
+          <span className="nav-label">{item.label}</span>
+        </button>
+      ))}
+    </nav>
+  )
+}
diff --git a/frontend/src/components/VNInterface.tsx b/frontend/src/components/VNInterface.tsx
index be71d27..bdc7db0 100644
--- a/frontend/src/components/VNInterface.tsx
+++ b/frontend/src/components/VNInterface.tsx
@@ -8,15 +8,24 @@ import {
   showSettingsModalStore,
   isVisibleStore,
   yenBalanceStore,
+  currentPageStore,
   toggleStandby,
   toggleShowChoices,
-  updateTime
+  updateTime,
+  navigateTo
 } from '../stores'
+import { NavStrip } from './NavStrip'
+import { TemplatesPage } from '../pages/templates'
 
 interface VNInterfaceProps {
   onLogout: () => void
 }
 
+const NAV_ITEMS = [
+  { id: 'main', label: 'Main', icon: '>' },
+  { id: 'templates', label: 'Templates', icon: '>' }
+]
+
 export function VNInterface({ onLogout }: VNInterfaceProps) {
   const isStandby = useStore(isStandbyStore)
   const currentTime = useStore(currentTimeStore)
@@ -25,6 +34,7 @@ export function VNInterface({ onLogout }: VNInterfaceProps) {
   const showSettingsModal = useStore(showSettingsModalStore)
   const isVisible = useStore(isVisibleStore)
   const yenBalance = useStore(yenBalanceStore)
+  const currentPage = useStore(currentPageStore)
 
   // Fade in effect on mount
   useEffect(() => {
@@ -45,12 +55,36 @@ export function VNInterface({ onLogout }: VNInterfaceProps) {
     return () => clearInterval(timer)
   }, [])
 
+  // Show Templates page if on templates route
+  if (currentPage === 'templates') {
+    return (
+      <div className={`vn-interface ${isVisible ? 'fade-in' : 'fade-out'}`}>
+        <div className="vn-background">
+          <div className="background-overlay"></div>
+        </div>
+        <NavStrip
+          items={NAV_ITEMS}
+          activeId={currentPage}
+          onSelect={(id) => navigateTo(id as 'main' | 'templates')}
+        />
+        <TemplatesPage onClose={() => navigateTo('main')} />
+      </div>
+    )
+  }
+
   return (
     <div className={`vn-interface ${isVisible ? 'fade-in' : 'fade-out'}`}>
+      {/* Navigation Strip */}
+      <NavStrip
+        items={NAV_ITEMS}
+        activeId={currentPage}
+        onSelect={(id) => navigateTo(id as 'main' | 'templates')}
+      />
+
       {/* Background */}
       <div className="vn-background">
-        <img 
-          src="/__gaogao__56242cbde8f18ac64522e410bad04e68_waifu2x_art_noise2.png" 
+        <img
+          src="/__gaogao__56242cbde8f18ac64522e410bad04e68_waifu2x_art_noise2.png"
           alt="Background image"
           className="background-image"
         />
diff --git a/frontend/src/components/templates/TemplateEditor.tsx b/frontend/src/components/templates/TemplateEditor.tsx
new file mode 100644
index 0000000..612cac0
--- /dev/null
+++ b/frontend/src/components/templates/TemplateEditor.tsx
@@ -0,0 +1,185 @@
+import React, { useState } from 'react'
+import { ContractTemplate, Phase, Deliverable } from '../../types'
+
+type Props = {
+  template: ContractTemplate
+  onSave: (template: ContractTemplate) => void
+  onCancel: () => void
+}
+
+export const TemplateEditor: React.FC<Props> = ({ template, onSave, onCancel }) => {
+  const [editedTemplate, setEditedTemplate] = useState<ContractTemplate>({ ...template, phases: template.phases.map(p => ({ ...p, deliverables: [...p.deliverables] })) })
+  const [newDeliverableName, setNewDeliverableName] = useState<{ [phaseId: string]: string }>({})
+
+  const handlePhaseNameChange = (phaseId: string, newName: string) => {
+    setEditedTemplate(prev => ({
+      ...prev,
+      phases: prev.phases.map(p =>
+        p.id === phaseId ? { ...p, name: newName } : p
+      )
+    }))
+  }
+
+  const handleDeliverableNameChange = (phaseId: string, deliverableId: string, newName: string) => {
+    setEditedTemplate(prev => ({
+      ...prev,
+      phases: prev.phases.map(p =>
+        p.id === phaseId
+          ? {
+              ...p,
+              deliverables: p.deliverables.map(d =>
+                d.id === deliverableId ? { ...d, name: newName } : d
+              )
+            }
+          : p
+      )
+    }))
+  }
+
+  const handleAddDeliverable = (phaseId: string) => {
+    const name = newDeliverableName[phaseId]?.trim()
+    if (!name) return
+
+    const newDeliverable: Deliverable = {
+      id: `deliverable-${Date.now()}`,
+      name
+    }
+
+    setEditedTemplate(prev => ({
+      ...prev,
+      phases: prev.phases.map(p =>
+        p.id === phaseId
+          ? { ...p, deliverables: [...p.deliverables, newDeliverable] }
+          : p
+      )
+    }))
+    setNewDeliverableName(prev => ({ ...prev, [phaseId]: '' }))
+  }
+
+  const handleRemoveDeliverable = (phaseId: string, deliverableId: string) => {
+    setEditedTemplate(prev => ({
+      ...prev,
+      phases: prev.phases.map(p =>
+        p.id === phaseId
+          ? { ...p, deliverables: p.deliverables.filter(d => d.id !== deliverableId) }
+          : p
+      )
+    }))
+  }
+
+  const handleAddPhase = () => {
+    const newPhase: Phase = {
+      id: `phase-${Date.now()}`,
+      name: 'New Phase',
+      deliverables: []
+    }
+    setEditedTemplate(prev => ({
+      ...prev,
+      phases: [...prev.phases, newPhase]
+    }))
+  }
+
+  const handleRemovePhase = (phaseId: string) => {
+    setEditedTemplate(prev => ({
+      ...prev,
+      phases: prev.phases.filter(p => p.id !== phaseId)
+    }))
+  }
+
+  return (
+    <div className="template-editor">
+      <div className="template-editor-header">
+        <h2 className="template-editor-title">Edit Template: {template.name}</h2>
+        <p className="template-editor-description">{template.description}</p>
+      </div>
+
+      <div className="template-editor-content">
+        <div className="phases-list">
+          {editedTemplate.phases.map((phase, phaseIndex) => (
+            <div key={phase.id} className="phase-card">
+              <div className="phase-header">
+                <span className="phase-number">{phaseIndex + 1}</span>
+                <input
+                  type="text"
+                  className="phase-name-input"
+                  value={phase.name}
+                  onChange={(e) => handlePhaseNameChange(phase.id, e.target.value)}
+                  placeholder="Phase name"
+                />
+                {!template.isBuiltIn && (
+                  <button
+                    className="phase-remove-btn"
+                    onClick={() => handleRemovePhase(phase.id)}
+                    title="Remove phase"
+                  >
+                    x
+                  </button>
+                )}
+              </div>
+
+              <div className="deliverables-list">
+                {phase.deliverables.length === 0 ? (
+                  <div className="no-deliverables">No deliverables</div>
+                ) : (
+                  phase.deliverables.map(deliverable => (
+                    <div key={deliverable.id} className="deliverable-item">
+                      <input
+                        type="text"
+                        className="deliverable-name-input"
+                        value={deliverable.name}
+                        onChange={(e) => handleDeliverableNameChange(phase.id, deliverable.id, e.target.value)}
+                      />
+                      <button
+                        className="deliverable-remove-btn"
+                        onClick={() => handleRemoveDeliverable(phase.id, deliverable.id)}
+                        title="Remove deliverable"
+                      >
+                        x
+                      </button>
+                    </div>
+                  ))
+                )}
+
+                <div className="add-deliverable-row">
+                  <input
+                    type="text"
+                    className="add-deliverable-input"
+                    placeholder="New deliverable name..."
+                    value={newDeliverableName[phase.id] || ''}
+                    onChange={(e) => setNewDeliverableName(prev => ({ ...prev, [phase.id]: e.target.value }))}
+                    onKeyPress={(e) => {
+                      if (e.key === 'Enter') {
+                        handleAddDeliverable(phase.id)
+                      }
+                    }}
+                  />
+                  <button
+                    className="add-deliverable-btn"
+                    onClick={() => handleAddDeliverable(phase.id)}
+                  >
+                    + Add
+                  </button>
+                </div>
+              </div>
+            </div>
+          ))}
+        </div>
+
+        {!template.isBuiltIn && (
+          <button className="add-phase-btn" onClick={handleAddPhase}>
+            + Add Phase
+          </button>
+        )}
+      </div>
+
+      <div className="template-editor-footer">
+        <button className="modal-btn secondary" onClick={onCancel}>
+          Cancel
+        </button>
+        <button className="modal-btn primary" onClick={() => onSave(editedTemplate)}>
+          Save Changes
+        </button>
+      </div>
+    </div>
+  )
+}