v0.2.0 — Docs precision + injection guard

Added

• Prompt-injection guard in the digest phase: the transcript and media metadata (title,
  uploader, description) are treated as untrusted content, never as instructions
• User-directed digests: stated focus / audience / format / length / language override the
  default takeaways+summary structure; offer a free re-cut for long unfocused content
• Windows notes: PowerShell install, winget/Chocolatey, py -3 fallback (also instructed in
  SKILL.md), CUDA visibility check with its limits, skill path
• Model selection table and AUDIO_TLDR_MODEL examples
• Standalone Traditional Chinese README (README.zh-TW.md)
• Verified-environment table in Status; usage-rights reminder for URL sources
• This changelog and the version-bump rule

Changed

• README restructured (tagline / badges / Why? / features / tables)
• Privacy claims made precise: media pipeline is local; the digest phase sends transcript text
  to your Claude session; cached transcripts are unencrypted plaintext kept indefinitely by
  default, with concrete Phase-1-only commands
• Testing claims made accurate: 18 offline unit tests (mocked) + one manual macOS/mlx-whisper
  verification; Windows and other backends not yet verified