RSC docs: add troubleshooting matrix for common setup/runtime failures

[justin808]

Problem

Current RSC docs describe happy-path setup, but they do not have a consolidated troubleshooting section for the most common setup/runtime failures.

As RSC adoption grows, users need fast diagnosis guidance without digging through PRs/issues.

Proposal

Add an RSC Troubleshooting section to docs with a symptom -> cause -> fix matrix.

Include at least:

1. TypeError: serverWebpackConfig is not a function (legacy webpack export mismatch).
2. Missing rsc_payload_route / payload endpoint 404s.
3. Missing 'use client' on interactive components (link Improve error messages when interactive component is missing 'use client' with RSC enabled #2394 and Docs: Clarify distinction between .client/.server file suffixes and 'use client' RSC directive #2405 context).
4. React version mismatch (RSC currently supports React 19.0.x in RoR Pro).
5. How to verify boundary behavior (server component JS not shipped; client component JS shipped).

Acceptance Criteria

• RSC docs have a troubleshooting page or section linked from main RSC docs.
• At least five concrete failure modes are documented with actionable fixes.
• Includes quick diagnostic commands/checks where possible.
• Cross-links to relevant open issues for deeper context (Improve error messages when interactive component is missing 'use client' with RSC enabled #2394, Docs: Clarify distinction between .client/.server file suffixes and 'use client' RSC directive #2405).

[justin808]

Deep-dive triage pass (2026-03-22):

• Domain: documentation
• Labels/Priority signals: enhancement, documentation, P2
• Current PR coverage: no open PR currently linked
• Proposed next step: add this to the new triage PR stack so it has explicit implementation ownership.

Question: Should this be batched with related docs issues in a single docs PR, or handled separately?

[justin808]

Verification on 2026-03-23: this appears implemented.

Current docs now include a dedicated troubleshooting page and links from main RSC docs:

• docs/oss/migrating/rsc-troubleshooting.md
• linked from docs/pro/react-server-components/index.md and the migration series

The troubleshooting page includes a large symptom/cause/fix matrix with actionable steps and diagnostics, covering the major RSC setup/runtime failure classes requested here.

Closing as completed. If a specific missing failure mode remains, please reopen with the exact symptom and target section to add.