chore: consolidate contrib-docs into docs-internal

[NathanFlurry]

Summary

• Consolidates scattered contrib-docs/ directories from docs/, engine/contrib-docs/, contrib-docs/, and rivetkit-typescript/contrib-docs/ into a unified docs-internal/ directory
• Replays the work from chore: move docs for cleaner nav #4199 which was closed without merging

Test plan

• Verify no broken references to old contrib-docs paths

[railway-app]

🚅 Deployed to the rivet-pr-4281 environment in rivet-frontend

Service	Status	Web	Updated (UTC)
mcp-hub	✅ Success (View Logs)	Web	Feb 24, 2026 at 6:11 am
frontend-inspector	🕐 Initializing (View Logs)	Web	Feb 24, 2026 at 6:11 am
frontend-cloud	🕐 Initializing (View Logs)	Web	Feb 24, 2026 at 6:11 am
ladle	❌ Build Failed (View Logs)	Web	Feb 24, 2026 at 6:10 am
website	🕒 Building (View Logs)	Web	Feb 24, 2026 at 6:10 am

[NathanFlurry]

• chore: consolidate contrib-docs into docs-internal #4281 👈 (View in Graphite)
• main

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[claude]

PR Review: chore: consolidate contrib-docs into docs-internal

Overall this is a clean organizational improvement. The goal is clear, and the GUARD.md content enhancement is a nice addition on top of the pure rename work. A few things worth looking at:

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Issues

1. Typo carried over in directory name

docs-internal/engine/design-choicse/EMBEDDED_KV.md preserves a typo from the original engine/contrib-docs/design-choicse/ path. Since the file is being moved anyway, this is a good opportunity to rename it to design-choices/.

2. RELEASING.md placed under engine/

The original contrib-docs/RELEASING.md lived at the repo root level and covers project-wide release processes (frontend deployment via scripts/git/promote-prod.sh, etc.) — not just the engine. Moving it to docs-internal/engine/RELEASING.md misrepresents its scope. docs-internal/RELEASING.md (top-level) would be more accurate.

3. docs symlink breaks existing path references

Creating docs -> website/src/content repurposes the docs/ entry that previously held internal engineering documentation. Any existing links, bookmarks, or tooling that referenced docs/engine/*.md paths (e.g., in PR descriptions, IDE notes, CI scripts) will now silently resolve to website/src/content/engine/... — which doesn't exist. Consider adding a note or README at the old path, or checking for references before merging.

4. Possible content loss in GUARD.md

The old docs/engine/GUARD.md documented runner WebSocket routing via:

• path match: /runners/connect
• Sec-Websocket-Protocol: comma-delimited pairs containing rivet_target.runner

The new consolidated docs-internal/engine/GUARD.md only describes runner routing via the x-rivet-target: runner header. If path-based runner routing still exists in the codebase, it should be preserved in the docs.

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Minor Notes

• The content improvements to GUARD.md (capitalization consistency — "WebSocket" not "websocket", backtick reference to HIBERNATING_WS.md) are good changes.
• The test plan item "Verify no broken references to old contrib-docs paths" is unchecked. A quick grep -r 'contrib-docs' . across the repo before merging would confirm nothing is missed.
• The PR description mentions this replays chore: move docs for cleaner nav #4199. Given that docs-internal/ already exists on main (from earlier partial work?), worth confirming there are no unexpected merge conflicts on the file renames before merging.