#20974: docs: add cspell spell checking for documentation

## Summary - Add cspell config and custom dictionary - Integrate spellcheck into check:docs pipeline - Fix typos found: sampel→sample, didnt→didn't, overlayed→overlaid - Problem: Docs-only PRs lack spellchecking; project/vendor terms were being flagged without an allowlist. Why it matters: Improves doc quality while keeping CI signal clean and reducing false positives for project terms. What changed: Added CSpell-based docs spellcheck, config + wordlist, and fixed a few typos in docs. What did NOT change (scope boundary): No runtime code, no gateway behavior, no API/contracts, no auth/token logic. ## Change Type (select all) - [ ] Bug fix - [X] Feature - [ ] Refactor - [ ] Docs - [ ] Security hardening - [X] Chore/infra ## Scope (select all touched areas) - [ ] Gateway / orchestration - [ ] Skills / tool execution - [ ] Auth / tokens - [ ] Memory / storage - [ ] Integrations - [ ] API / contracts - [ ] UI / DX - [X] CI/CD / infra ## Linked Issue/PR - Closes # - Related # ## User-visible / Behavior Changes Docs CI now runs spellcheck via CSpell; a few doc typos corrected. ## Security Impact (required) - New permissions/capabilities? `No` - Secrets/tokens handling changed? `No` - New/changed network calls? `No` - Command/tool execution surface changed? `No` - Data access scope changed? `No` - If any `Yes`, explain risk + mitigation: N/A ## Repro + Verification ### Environment - OS: macOS - Runtime/container: Node 22 + pnpm - Model/provider: - Integration/channel (if any): - Relevant config (redacted): ### Steps 1. pnpm install 2.pnpm check:docs ### Expected - Docs checks pass including CSpell. ### Actual - Docs checks pass including CSpell. ## Evidence Attach at least one: - [ ] Failing test/log before + passing after - [ ] Trace/log snippets - [ ] Screenshot/recording - [ ] Perf numbers (if relevant) ## Human Verification (required) What you personally verified (not just CI), and how: - Verified scenarios: Ran pnpm check:docs locally after installing deps. - Edge cases checked: Verified CSpell allows project/vendor terms via wordlist. - What you did **not** verify: Full CI pipeline; non-docs jobs. ## Compatibility / Migration - Backward compatible? `Yes` - Config/env changes? `No` - Migration needed? `No` - If yes, exact upgrade steps: N/A ## Failure Recovery (if this breaks) - How to disable/revert this change quickly: Remove the CSpell step from check:docs and delete .cspell.json - Files/config to restore: package.json, .cspell.json, .cspell-words.txt - Known bad symptoms reviewers should watch for: Docs CI failing due to missing/incorrect wordlist entries. ## Risks and Mitigations List only real risks for this PR. Add/remove entries as needed. If none, write `None`. - Risk: Wordlist could become too permissive over time. - Mitigation: Keep the list curated; only add project/vendor terms and documented jargon. <!-- greptile_comment --> <h3>Greptile Summary</h3> Adds CSpell-based spellchecking to the docs CI pipeline with a custom wordlist for project-specific terms. Fixed typos: `sampel`→`sample`, `didnt`→`didn't`, `doesnt`→`doesn't`, and `overlayed`→`overlaid` across documentation files. - Integrates `cspell` 9.6.4 as a dev dependency - Adds `.cspell.json` config with custom dictionary pointing to `docs/.cspell-words.txt` - Custom wordlist includes 606 project/vendor terms (OpenClaw, Ollama, service names, technical jargon) - Ignores `node_modules`, `dist`, and `docs/zh-CN` (auto-generated translations) - Updates `check:docs` script to include spellcheck step <h3>Confidence Score: 4/5</h3> - This PR is safe to merge with minimal risk once the ja-JP ignorePath is added. - Clean docs-only change with proper configuration and typo fixes. One minor issue: `docs/ja-JP` should be added to `ignorePaths` since it's generated content like `zh-CN`. Otherwise, implementation is solid with appropriate scope (CI/docs only), correct dependency version pinning, and proper integration into the docs check pipeline. - .cspell.json needs `docs/ja-JP/**` added to ignorePaths; all other files are good _{Last reviewed commit: 24171aa} <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} <!-- /greptile_comment -->