docs: fix stale release/build instructions and rewrite devbox guide

[abueide]

Summary

Fixes stale release/build documentation that no longer matches master. All findings were verified against the actual CI workflow (.github/workflows/release.yml), root and example devbox.json scripts, and package.json before editing — no speculative changes.

CONTRIBUTING.md

• Setup: yarn bootstrap does not exist. Replaced with devbox shell (init hook runs yarn install) or plain yarn install.
• Type-check: yarn typescript → yarn typecheck (the script was renamed; the old name errors out).
• E2E: the yarn e2e … command set no longer exists. Replaced with the current Devbox/Detox flow run from the example workspaces (examples/e2e-latest, examples/e2e-compat), plus a pointer to examples/SHARED_E2E_SETUP.md.
• Example paths: /example/ → examples/AnalyticsReactNativeExample/ (the old top-level dir is gone; only the examples/ tree exists).
• Release section: named the wrong workflow (Publish, which is actually the unrelated Publish E2E CLI). Corrected to the Release workflow and its dry-run / beta / production types.

wiki/release.md

• Removed the nonexistent --config=shells/devbox-fast.json flag from the sync-versions and release-dry-run commands. There is no shells/ directory; those scripts live in the root devbox.json and CI invokes them as devbox run <script>.

wiki/devbox.md (rewrite)

The old guide described an architecture that has since moved out of this repo. The Android/iOS SDK provisioning, emulator/simulator management, and device definitions now live in the reusable Devbox plugins in segment-integrations/mobile-devtools, consumed by the example workspaces via include. The rewrite:

• Documents the two tiers: the lean root env (build/test/lint/release only) and the example/E2E envs that pull in the mobile-devtools React Native plugin.
• Removes dead references to nix/, shells/, examples/E2E/, and ci-e2e-full.yml.
• Points at the plugin command surface (start:emu/start:sim/start:android/start:ios, doctor, etc.) and the committed devbox.d/ device lock files.
• Corrects the Releases note: npm publishing uses OIDC trusted publishing with provenance, not NPM_TOKEN.

Validation

• Pre-commit hook ran the full unit suite on commit: 69 suites, 479 passed (1 todo).
• All replacement paths, scripts, and workflow names were confirmed to exist on master (and in mobile-devtools for the plugin references).

Notes for reviewers

• wiki/scripts.md and wiki/nix.md may contain related stale references (e.g. to shells//nix/); I scoped this PR to the release/build-facing docs. Happy to follow up on those separately.

🤖 Generated with Claude Code

[abueide]

Updated: renamed wiki/release.md → root RELEASING.md to match the convention used across the other Segment SDK repos (analytics-swift, analytics-kotlin, analytics-next all use a root RELEASING.md). The rename preserves history (git mv), and the references in CONTRIBUTING.md and wiki/devbox.md were updated to point at the new path. No content changes beyond the earlier stale-command fixes.