fix: resolve 3 community-reported bugs (#2915, #2917, #2918)

- background_output: snapshot read cursor before consuming, restore on
  /undo message removal so re-reads return data (fixes #2915)
- MCP loader: preserve oauth field in transformMcpServer, add scope/
  projectPath filtering so local-scoped MCPs only load in matching
  directories (fixes #2917)
- runtime-fallback: add 'reached your usage limit' to retryable error
  patterns so quota exhaustion triggers model fallback (fixes #2918)

Verified: bun test (4606 pass / 0 fail), tsc --noEmit clean

src/features/claude-code-mcp-loader/loader.ts

@@ -10,6 +10,7 @@ import type {
 } from "./types"
 import { transformMcpServer } from "./transformer"
 import { log } from "../../shared/logger"
+import { shouldLoadMcpServer } from "./scope-filter"
 
 interface McpConfigPath {
   path: string
@@ -75,6 +76,7 @@ export async function loadMcpConfigs(
   const loadedServers: LoadedMcpServer[] = []
   const paths = getMcpConfigPaths()
   const disabledSet = new Set(disabledMcps)
+  const cwd = process.cwd()
 
   for (const { path, scope } of paths) {
     const config = await loadMcpConfigFile(path)
@@ -86,6 +88,15 @@ export async function loadMcpConfigs(
         continue
       }
 
+      if (!shouldLoadMcpServer(serverConfig, cwd)) {
+        log(`Skipping MCP server "${name}" because local scope does not match cwd`, {
+          path,
+          projectPath: serverConfig.projectPath,
+          cwd,
+        })
+        continue
+      }
+
       if (serverConfig.disabled) {
         log(`Disabling MCP server "${name}"`, { path })
         delete servers[name]