docs(ec2): fix the ffmpeg ~/.local/bin hint in the EC2 guide (#8897)

[bolichen97]

Addresses the documentation surface of #8897 that PR #8937 does not cover.

Why this is separate from #8937

#8937 is review-ready and CI-green, and it fixes the doctor hint in src/kiro_crew/cli_doctor.py plus the tests. It does not touch the second surface the issue flags. This PR is now scoped to that single missing piece so the two don't overlap. Its net diff is one file.

Change

• docs/guides/remote-crew-on-ec2.md (line ~137): the ffmpeg: not found note no longer tells users to drop a static build into ~/.local/bin and claim auto-detection (a directory the resolver never searches). It now says to install ffmpeg into /usr/local/bin (a location the resolver searches; not in the AL2023 repos), or fetch a decoder from the dashboard Speech-to-Text card (Settings > Voice, then Download now) via the POST /api/stt/ffmpeg/download path added in feat(stt): fetch the pinned ffmpeg decoder for source installs #8427.

Tests

N/A -- doc-only change, no code touched.

Manual verification

N/A -- unit coverage sufficient; verified scripts/docs-lint.sh passes clean on the changed file.

Note

If #8937 merges first, this remains a clean, non-conflicting doc-only follow-up. If a maintainer prefers a single PR, the EC2 guide change can instead be cherry-picked onto #8937 and this PR closed.

Closes #8897

[github-actions]

Design Review (Fable 5) — ✅ PASS

Design-level review of b2ee5bc0fcce5c27f83bd19c8cc1491002726c0d — updated in place on each push. A BLOCK verdict blocks PR readiness; PASS/CONCERNS are advisory.

Design-Verdict: PASS

Corrects a doc hint the resolver deliberately contradicts — ~/.local/bin was removed from the candidate list as a security decision (transcribe.py:92) — and both replacement remedies verifiably exist.

[DESIGN-REVIEWED] b2ee5bc

[github-actions]

Opus 4.8 Review — ✅ no blocking findings

Reviewed b2ee5bc0fcce5c27f83bd19c8cc1491002726c0d — this comment is updated in place on each push.

Review details

No findings.

[OPUS-REVIEWED] b2ee5bc

Verdict parsed from the review's SHA-scoped output markers for commit b2ee5bc0fcce5c27f83bd19c8cc1491002726c0d.

False positive or not applicable? A repository writer can comment:
/ai-review override fable b2ee5bc0fcce5c27f83bd19c8cc1491002726c0d: <one-sentence reason>

[github-actions]

GPT 5.6 Review — ✅ no blocking findings

GPT 5.6 completed its review of b2ee5bc0fcce5c27f83bd19c8cc1491002726c0d and found no blocking issues.

This comment is updated in place on each push.

Review details

No findings.
[GPT-REVIEWED] b2ee5bc

False positive or not applicable? A repository writer can comment:
/ai-review override gpt b2ee5bc0fcce5c27f83bd19c8cc1491002726c0d: <one-sentence reason>

[github-actions]

First Principles Review (Fable 5) — ⏭️ skipped

Revision b2ee5bc0fcce5c27f83bd19c8cc1491002726c0d ships no reviewable capability (docs, tests or generated files only), so there is nothing to inventory. Advisory — does not block merge.