docs: align Devvit Web and mod tool documentation

[cedaraspen]

Summary

• fix the mod-tool onboarding path and replace the stale tutorial stub with current guidance
• standardize Devvit Web package imports and clarify /api/... versus /internal/... endpoint conventions across guides and capability docs
• align playtest, upload, publish, and launch guidance, including adding a devvit publish CLI section
• correct documentation mismatches for menu user types, mod-action trigger naming, submitComment, submitCustomPost preview guidance, and subreddit subscription approval language
• update the Reddit API doc generator script so future generated output keeps the intended title

Testing

• git diff --check
• repo commit hooks (TruffleHog) passed during both commits
• docs build not run in this environment because node, npm, and yarn are unavailable