feat: fix slash commands, add badge UI, multi-provider management

Slash commands:
- Fix skills not appearing (removed non-existent `enabled` filter)
- Add badge/capsule UI for prompt-type commands (/compact, /review, etc.)
- SDK-native commands sent directly; CLI-only commands expanded to prompts
- /clear now resets SDK session and clears database messages
- /cost shows actual aggregated token usage statistics
- Keyboard: Backspace/Escape to remove badge, arrow keys auto-scroll popover
- Add /memory command for editing CLAUDE.md

Multi-provider management:
- CRUD API for API providers with SQLite storage
- ProviderManager UI with quick presets (GLM, Kimi, MiniMax, etc.)
- Dynamic model labels based on active provider
- Environment variable injection with conflict resolution

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/api/chat/sessions/[id]/route.ts

@@ -1,5 +1,5 @@
 import { NextRequest } from 'next/server';
-import { deleteSession, getSession, updateSessionWorkingDirectory, updateSessionTitle, updateSessionMode } from '@/lib/db';
+import { deleteSession, getSession, updateSessionWorkingDirectory, updateSessionTitle, updateSessionMode, clearSessionMessages } from '@/lib/db';
 
 export async function GET(
   _request: NextRequest,
@@ -40,6 +40,9 @@ export async function PATCH(
     if (body.mode) {
       updateSessionMode(id, body.mode);
     }
+    if (body.clear_messages) {
+      clearSessionMessages(id);
+    }
 
     const updated = getSession(id);
     return Response.json({ session: updated });

src/app/api/providers/[id]/activate/route.ts

@@ -0,0 +1,52 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { activateProvider, deactivateAllProviders, getProvider } from '@/lib/db';
+import type { ErrorResponse } from '@/types';
+
+interface RouteContext {
+  params: Promise<{ id: string }>;
+}
+
+export async function POST(request: NextRequest, context: RouteContext) {
+  const { id } = await context.params;
+
+  try {
+    // Parse optional body — { active: boolean }, defaults to true
+    let active = true;
+    try {
+      const body = await request.json();
+      if (typeof body.active === 'boolean') {
+        active = body.active;
+      }
+    } catch {
+      // No body or invalid JSON — default to activate
+    }
+
+    if (!active) {
+      deactivateAllProviders();
+      return NextResponse.json({ success: true, active: false });
+    }
+
+    const existing = getProvider(id);
+    if (!existing) {
+      return NextResponse.json<ErrorResponse>(
+        { error: 'Provider not found' },
+        { status: 404 }
+      );
+    }
+
+    const activated = activateProvider(id);
+    if (!activated) {
+      return NextResponse.json<ErrorResponse>(
+        { error: 'Failed to activate provider' },
+        { status: 500 }
+      );
+    }
+
+    return NextResponse.json({ success: true, active: true });
+  } catch (error) {
+    return NextResponse.json<ErrorResponse>(
+      { error: error instanceof Error ? error.message : 'Failed to activate provider' },
+      { status: 500 }
+    );
+  }
+}

src/app/api/providers/[id]/route.ts

@@ -0,0 +1,93 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getProvider, updateProvider, deleteProvider } from '@/lib/db';
+import type { ProviderResponse, ErrorResponse, UpdateProviderRequest, ApiProvider } from '@/types';
+
+interface RouteContext {
+  params: Promise<{ id: string }>;
+}
+
+function maskApiKey(provider: ApiProvider): ApiProvider {
+  let maskedKey = provider.api_key;
+  if (maskedKey && maskedKey.length > 8) {
+    maskedKey = '***' + maskedKey.slice(-8);
+  }
+  return { ...provider, api_key: maskedKey };
+}
+
+export async function GET(_request: NextRequest, context: RouteContext) {
+  const { id } = await context.params;
+
+  try {
+    const provider = getProvider(id);
+    if (!provider) {
+      return NextResponse.json<ErrorResponse>(
+        { error: 'Provider not found' },
+        { status: 404 }
+      );
+    }
+
+    return NextResponse.json<ProviderResponse>({ provider: maskApiKey(provider) });
+  } catch (error) {
+    return NextResponse.json<ErrorResponse>(
+      { error: error instanceof Error ? error.message : 'Failed to get provider' },
+      { status: 500 }
+    );
+  }
+}
+
+export async function PUT(request: NextRequest, context: RouteContext) {
+  const { id } = await context.params;
+
+  try {
+    const body: UpdateProviderRequest = await request.json();
+
+    const existing = getProvider(id);
+    if (!existing) {
+      return NextResponse.json<ErrorResponse>(
+        { error: 'Provider not found' },
+        { status: 404 }
+      );
+    }
+
+    // If api_key starts with ***, the client sent back a masked value — don't update it
+    if (body.api_key && body.api_key.startsWith('***')) {
+      delete body.api_key;
+    }
+
+    const updated = updateProvider(id, body);
+    if (!updated) {
+      return NextResponse.json<ErrorResponse>(
+        { error: 'Failed to update provider' },
+        { status: 500 }
+      );
+    }
+
+    return NextResponse.json<ProviderResponse>({ provider: maskApiKey(updated) });
+  } catch (error) {
+    return NextResponse.json<ErrorResponse>(
+      { error: error instanceof Error ? error.message : 'Failed to update provider' },
+      { status: 500 }
+    );
+  }
+}
+
+export async function DELETE(_request: NextRequest, context: RouteContext) {
+  const { id } = await context.params;
+
+  try {
+    const deleted = deleteProvider(id);
+    if (!deleted) {
+      return NextResponse.json<ErrorResponse>(
+        { error: 'Provider not found' },
+        { status: 404 }
+      );
+    }
+
+    return NextResponse.json({ success: true });
+  } catch (error) {
+    return NextResponse.json<ErrorResponse>(
+      { error: error instanceof Error ? error.message : 'Failed to delete provider' },
+      { status: 500 }
+    );
+  }
+}

src/app/api/providers/route.ts

@@ -0,0 +1,47 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getAllProviders, createProvider } from '@/lib/db';
+import type { ProvidersResponse, ProviderResponse, ErrorResponse, CreateProviderRequest, ApiProvider } from '@/types';
+
+function maskApiKey(provider: ApiProvider): ApiProvider {
+  let maskedKey = provider.api_key;
+  if (maskedKey && maskedKey.length > 8) {
+    maskedKey = '***' + maskedKey.slice(-8);
+  }
+  return { ...provider, api_key: maskedKey };
+}
+
+export async function GET() {
+  try {
+    const providers = getAllProviders().map(maskApiKey);
+    return NextResponse.json<ProvidersResponse>({ providers });
+  } catch (error) {
+    return NextResponse.json<ErrorResponse>(
+      { error: error instanceof Error ? error.message : 'Failed to get providers' },
+      { status: 500 }
+    );
+  }
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const body: CreateProviderRequest = await request.json();
+
+    if (!body.name) {
+      return NextResponse.json<ErrorResponse>(
+        { error: 'Missing required field: name' },
+        { status: 400 }
+      );
+    }
+
+    const provider = createProvider(body);
+    return NextResponse.json<ProviderResponse>(
+      { provider: maskApiKey(provider) },
+      { status: 201 }
+    );
+  } catch (error) {
+    return NextResponse.json<ErrorResponse>(
+      { error: error instanceof Error ? error.message : 'Failed to create provider' },
+      { status: 500 }
+    );
+  }
+}