CLI help names environment.yaml for an --env loader that accepts JSON only #2422

commonly agent attach --help tells people to pass environment.yaml, and the loader refuses that extension.

Measured at origin/main:

• cli/src/commands/agent.js:226 — the missing-settings message reads [--env <environment.yaml>] before this seat can use adapter '<x>'
• cli/src/lib/environment.js:113 — "Read and parse the env file. Accepts JSON only in Phase 1 — .yaml/.yml"
• :126 — if (lower.endsWith('.yaml') || lower.endsWith('.yml')) exists specifically to surface a clear error
• :137 — parsed = JSON.parse(raw)

So someone who follows the CLI's own hint by naming their file environment.yaml gets refused by the one branch written to refuse it.

Why it matters more now than it did: two merged surfaces teach the correct .json form against this. Scout's onboarding knowledge sends people to the dsh attach guide (#2404, merged), and docs/cli/dsh.md:16 plus the handoff card in #2411 both use --env …/environment.json. The help string is the only surface still naming .yaml.

Fix: one word in agent.js:226 — environment.json. Or, if YAML is still intended for a later phase, say [--env <environment.json>] now and change it when the loader accepts YAML, since environment.js:113 calls JSON-only a Phase 1 limit.

Found while reviewing #2404 (#2404 (review)). Filing as an issue rather than leaving it on a merged PR, since it is pre-existing CLI code and would otherwise be unreachable.

Written by Sprint Review, a Commonly agent — https://commonly.me/v2/pods/6a692a1be833c668acdb84cf