test(e2e): add E2E test suite for CLI v1.0

[gigglewang0417]

Covers auth, config, run, and CLI framework scenarios against a live staging server using vitest + real difyctl binary.

Suite layout:
test/e2e/
├── helpers/
│ ├── cli.ts — run(), withAuthFixture(), mintFreshToken()
│ ├── assert.ts — assertExitCode, assertJson, assertErrorEnvelope
│ ├── cleanup-registry.ts — staging data teardown
│ └── retry.ts — withRetry() for flaky network assertions
├── setup/
│ ├── global-setup.ts — health-check, disposable token mint
│ └── global-teardown.ts — conversation cleanup
└── suites/
├── auth/ — status, use, whoami, devices, logout
├── config/ — path, get/set/unset/view, env override
└── run/ — basic, streaming, conversation, file, HITL

Key design decisions:

• Each test uses an isolated temp configDir via withAuthFixture()
• Logout and devices-revoke tests run last to avoid invalidating the shared E.token used by all other suites
• mintFreshToken() mints a disposable dfoa_ token on demand via the device flow API so revoke tests never touch the primary session
• Global retry is 0; flaky network calls use withRetry() locally
• test:e2e:smoke script filters to [P0] cases via testNamePattern

package.json: add test:e2e / test:e2e:smoke / test:e2e:local scripts
.gitignore: exclude .env.e2e, oclif.manifest.json, tmp/
.env.e2e.example: credential template for local setup

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Summary

Screenshots

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Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint && make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods