[DibbayajyotiRoy]

This PR locks the stdout contract ahead of the TUI work (spinners, colour). Scripts and AI agents parse this CLI's stdout and exit codes, so the terminal work must not change either.

What it adds

Only new files: internal/cmd/*_golden_test.go and internal/cmd/testdata/golden/.... No existing file is touched.

TestGolden runs every command and its main modes in-process against a fake API, the way a non-interactive caller sees them (stdout is not a terminal, so JSON by default). For each case it compares:

• stdout, byte for byte (<case>.stdout), and the exit code (<case>.exit)
• stderr (<case>.stderr) only where it is itself machine output: the JSON-mode problem document
• files the command writes with -o / --screenshot-dir (<case>.file.*)

Every case runs three times: plain, NO_COLOR=1, CI=true. All three must produce the same stdout and exit code, stdout and stderr must contain no ANSI escape, and stderr no carriage return (an in-place spinner line). The tests run with a colour-capable TERM, so only the non-terminal output keeps colour off.

Coverage

• scrape: html, markdown, text, json envelope, pdf (base64), --jsonl, --json, --extract, --ai, --autoparse, --links, --network-capture, --screenshot, -o, target 4xx/5xx and --allowed-status, scrape - (stdin, many URLs), API and usage errors
• batch: submit (file, jsonl, stdin, --wait), wait (completed, failed, cancelled, pending exit 11), get, list, results, content, cancel, close, retry, append
• sessions, logs, status, usage, browser url, config, auth, login, logout, schema, docs, version, exit-codes, mcp install, skill install, init, and usage errors from the root command
• The same commands in human mode (*_human cases), reached through the existing humanOutput hook because that is the only way to get there without a pty

Timestamps, request ids, build identity (version, Go, OS, arch), the fake server address and temp paths are replaced by placeholders in goldenNormalize (documented there). The embedded JSON Schemas are locked by sha256.

Updating

After an intended output change:

go test ./internal/cmd -run TestGolden -update     # or GOLDEN_UPDATE=1 go test ./...

then review the diff. -update also removes golden files no case produces.

Not covered

• Behaviour that needs a real terminal: the interactive prompts (login, init, batch cancel, sessions delete), and what NO_COLOR / CI do on a TTY. That needs a pty.
• --help text and shell completion output.
• stderr prose and OS-specific error text (a refused connection), which are not a stable contract.

[DibbayajyotiRoy]

Merged into #4, so the golden tests run against the terminal UI changes they protect.