feat: 模型级联菜单、逐回合分叉、折叠态会话切换、划选引用与界面缩放

- 模型菜单改为级联悬浮结构：服务商独立成行，悬浮其上时模型列表浮出左侧；

apps/desktop/src/main/ipc.ts

@@ -181,6 +181,13 @@ export function registerIpc(): AgentService {
   // 会话末尾分叉为新会话（pi fork，原会话保留）
   ipcMain.handle('session:fork', () => pass(() => service.forkSession()))
 
+  // 从会话树上的锚点分叉为新会话（'at' 含该条为止 / 'before' 到其父条目为止）
+  ipcMain.handle('session:forkAt', (_event, entryId: unknown, position: unknown) => {
+    if (typeof entryId !== 'string' || !entryId.trim()) throw new Error('invalid entry id')
+    if (position !== 'at' && position !== 'before') throw new Error('invalid fork position')
+    return pass(() => service.forkSessionAt(entryId, position))
+  })
+
   // ---- 应用设置 ----
   ipcMain.handle('settings:get', () => service.getSettings())
 

apps/desktop/src/main/pi/agent-service.ts

@@ -2,13 +2,13 @@ import { app, dialog, shell } from 'electron'
 import { nativeTheme } from 'electron'
 import { existsSync, mkdirSync, readFileSync, readdirSync, statSync, writeFileSync } from 'node:fs'
 import { dirname, join } from 'node:path'
+import { homedir } from 'node:os'
 import {
   createAgentSessionRuntime,
   createAgentSessionServices,
   createAgentSessionFromServices,
   estimateTokens,
   getAgentDir,
-  loadSkills,
   SessionManager,
   type AgentSession,
   type AgentSessionEvent,
@@ -476,7 +476,7 @@ export class AgentService {
     ]
     const byKey = new Map(breakdown.map((b) => [b.key, b]))
     const systemTokens = Math.ceil(session.systemPrompt.length / 4)
-    const skillsTokens = this.estimateSkillsTokens()
+    const skillsTokens = this.estimateSkillsTokens(session)
     byKey.get('systemPrompt')!.tokens = Math.max(0, systemTokens - skillsTokens)
     byKey.get('skills')!.tokens = skillsTokens
 
@@ -522,15 +522,14 @@ export class AgentService {
     }
   }
 
-  /** 技能清单注入系统提示词的 token 估算（按 cwd 缓存；技能清单会话内极少变化） */
-  private estimateSkillsTokens(): number {
+  /** 技能清单注入系统提示词的 token 估算（按 cwd 缓存；技能清单会话内极少变化）。
+   * 数据源与系统提示词同源（resource loader，覆盖 ~/.agents/skills 等全部默认位置） */
+  private estimateSkillsTokens(session: AgentSession): number {
     if (this.skillsEstimate && this.skillsEstimate.cwd === this.cwd) return this.skillsEstimate.value
     let value = 0
     try {
-      const loaded = loadSkills({ cwd: this.cwd, agentDir: getAgentDir(), skillPaths: [], includeDefaults: true })
-      value = Math.ceil(
-        loaded.skills.reduce((sum, s) => sum + s.name.length + (s.description?.length ?? 0) + 8, 0) / 4
-      )
+      const loaded = session.resourceLoader.getSkills()
+      value = Math.ceil(loaded.skills.reduce((sum, s) => sum + s.name.length + s.description.length + 8, 0) / 4)
     } catch {
       value = 0
     }
@@ -633,18 +632,11 @@ export class AgentService {
 
   async listChatResources(): Promise<ChatResources> {
     const runtime = await this.getRuntime()
-    let skills: ChatResources['skills'] = []
-    try {
-      const loaded = loadSkills({
-        cwd: this.cwd,
-        agentDir: getAgentDir(),
-        skillPaths: [],
-        includeDefaults: true
-      })
-      skills = loaded.skills.map((s) => ({ name: s.name, description: s.description ?? '' }))
-    } catch (err) {
-      console.error('[agent-service] load skills failed:', err)
-    }
+    // 与系统提示词同源：resource loader 的技能发现（含 ~/.agents/skills 与工作区 .agents/skills）
+    const skills = runtime.session.resourceLoader.getSkills().skills.map((s) => ({
+      name: s.name,
+      description: s.description
+    }))
     const commands = runtime.session.promptTemplates.map((t) => ({
       name: t.name,
       description: t.description ?? '',
@@ -653,30 +645,31 @@ export class AgentService {
     return { commands, skills }
   }
 
-  /** 设置页「技能 / 命令」详情列表（含来源文件与资源目录，供打开/刷新） */
+  /** 设置页「技能 / 命令」详情列表（含来源文件与资源目录，供打开/刷新）。
+   * 技能取自 resource loader（与系统提示词同源，覆盖 ~/.agents/skills 与工作区 .agents/skills）。 */
   async listResourceDetails(): Promise<ResourceDetails> {
     const agentDir = getAgentDir()
     const dirs = {
       globalSkills: join(agentDir, 'skills'),
+      globalAgentsSkills: join(homedir(), '.agents', 'skills'),
       projectSkills: join(this.cwd, '.pi', 'skills'),
+      projectAgentsSkills: join(this.cwd, '.agents', 'skills'),
       globalCommands: join(agentDir, 'prompts'),
       projectCommands: join(this.cwd, '.pi', 'prompts')
     }
-    let skills: SkillDetail[] = []
+    const skills: SkillDetail[] = []
     try {
-      const loaded = loadSkills({
-        cwd: this.cwd,
-        agentDir,
-        skillPaths: [],
-        includeDefaults: true
-      })
-      skills = loaded.skills.map((s) => ({
-        name: s.name,
-        description: s.description ?? '',
-        filePath: s.filePath,
-        scope: s.sourceInfo?.scope === 'user' ? 'user' : 'project',
-        disableModelInvocation: Boolean(s.disableModelInvocation)
-      }))
+      const runtime = await this.getRuntime()
+      for (const s of runtime.session.resourceLoader.getSkills().skills) {
+        skills.push({
+          name: s.name,
+          description: s.description,
+          filePath: s.filePath,
+          // 与 resource loader 的默认归类一致：无来源信息时按用户级
+          scope: s.sourceInfo?.scope === 'project' ? 'project' : 'user',
+          disableModelInvocation: Boolean(s.disableModelInvocation)
+        })
+      }
     } catch (err) {
       console.error('[agent-service] load skill details failed:', err)
     }
@@ -953,6 +946,12 @@ export class AgentService {
     const mr = runtime.session.modelRuntime
     const credentials = await mr.listCredentials()
     const credSet = new Set(credentials.map((c) => `${c.providerId}:${c.type}`))
+    // 自定义提供商的 apiKey 存在 models.json（不进凭据存储），有 key 即视为已配置
+    const customKeyed = new Set(
+      Object.entries(this.readModelsConfig().providers)
+        .filter(([, v]) => Boolean((v as { apiKey?: unknown })?.apiKey))
+        .map(([id]) => id)
+    )
     const providers = mr
       .getProviders()
       .map((p) => {
@@ -960,7 +959,7 @@ export class AgentService {
         return {
           id: pid,
           name: String(p.name ?? pid),
-          hasApiKey: credSet.has(`${pid}:api_key`),
+          hasApiKey: credSet.has(`${pid}:api_key`) || customKeyed.has(pid),
           isOAuth: credSet.has(`${pid}:oauth`),
           models: mr
             .getModels(pid)
@@ -1076,7 +1075,17 @@ export class AgentService {
     if (!leafId) {
       throw new Error('会话还没有可分叉的内容')
     }
-    const result = await runtime.fork(leafId, { position: 'at' })
+    await this.forkSessionAt(leafId, 'at')
+  }
+
+  /** 从会话树上的任意锚点分叉新会话：'at' = 新会话包含该条为止；'before' = 到其父条目为止 */
+  async forkSessionAt(entryId: string, position: 'at' | 'before'): Promise<void> {
+    const runtime = await this.getRuntime()
+    const session = runtime.session
+    if (session.isStreaming) {
+      await session.abort()
+    }
+    const result = await runtime.fork(entryId, { position })
     if (result.cancelled) return
   }