docs: add Xquik evidence guidance and fix validation

[kriptoburak]

Summary

• update the Typefully Skill to use canonical Xquik x-twitter-scraper, REST, and MCP research outputs as source evidence
• keep Typefully responsible for draft creation, scheduling, and publishing
• update stale CLI version expectations from 0.0.1 to package version 0.3.0
• fix interactive text validation for the prompt library's possible undefined value
• add the required Xquik independence notice and clear prohibited dash forms in the edited Skill

Independent Repository Fix

Strict TypeScript checking failed because the interactive prompt validator called .trim() on a value typed as possibly undefined. It now uses a null-safe check, so empty and undefined prompt values return the existing validation message without crashing. The full typecheck now passes. The existing version regression tests also now match package version 0.3.0.

Validation

• pnpm install --frozen-lockfile
• pnpm typecheck
• pnpm build
• pnpm test - 20 passed
• pnpm exec biome check src/commands/interactive.ts tests/cli.test.ts package.json
• git diff --check
• scanned the complete diff for credentials and private implementation details

The repository-wide Biome command still reports pre-existing formatting and import findings in untouched files. This PR does not expand into a repository-wide reformat.

Xquik is an independent third-party service. Not affiliated with X Corp. "Twitter" and "X" are trademarks of X Corp.

[kriptoburak]

Revalidated and republished the contribution as signed commits at head 01cb946. The independent fix guards the interactive prompt validator against the library's possible undefined value, restoring strict typechecking without changing the existing validation message. Validation passes: frozen install, typecheck, build, 20 tests, focused Biome checks, and diff checks. The repository-wide Biome findings remain pre-existing in generated or untouched files.