Logbeam 0.2.1

Fixes from two rounds of testing in Chromium.

Fixed

• A slow regex could freeze the tab. Patterns with nested quantifiers like (a+)+$ are refused at once,
  and every regex search now runs in a worker that is stopped after 2 seconds.
• Mask left private keys readable. The whole base64 body of a PEM key is now flagged and masked, not
  just its BEGIN line.
• Missed secrets: SECRET_KEY=, access_token, refresh_token, token=, private_key,
  Authorization: Basic, quoted passwords with spaces, and URL passwords that contain @.
• Masking revealed part of the value. Secrets are now replaced by a fixed ********; only a public type
  prefix such as AKIA or ghp_ stays visible, and the length isn't revealed either.
• Format JSON changed numbers: 12345678901234567890 became 12345678901234567000 and 1.10 became
  1.1. Numbers are now copied exactly as written.
• Dark mode: pages that already have a dark theme are left alone instead of being turned light; turning it
  off no longer reloads the page; after a reload the popup no longer shows it as on; it is remembered for a
  site only when you tick "Remember", and forgetting a site releases its permission.
• Shortcuts moved from Alt+Shift (which switches the keyboard layout on Windows) to Ctrl+Shift+L and
  Ctrl+Shift+K. The popup shows the shortcuts actually assigned and links to chrome://extensions/shortcuts.
• Silent failures: on pages Chrome doesn't allow (chrome://, the Web Store, local files without file
  access, the PDF viewer) the popup now says why, and shortcuts and the context menu show a red ! on the
  toolbar icon with the reason. The popup no longer closes when opening the viewer failed.
• pino and zap logs show a date and a level name instead of an epoch and 30.
• "Collapse" also merges repeated errors that have the same stack trace.
• Timestamps in syslog, nginx/Apache, Android logcat and epoch formats; Android and [W] levels and DBG;
  prose like "no error here" is no longer marked as an error.
• Text tools: tel and number inputs, textareas inside web components, and editors with no selection;
  Esc closes the panel without also reaching the page.
• Cron: 0,7 is Sunday once, backwards ranges and impossible dates (31 February) are reported, 7-field
  Quartz expressions with a year, clearer wording for day steps.
• JWT dates written in milliseconds, micro- and nanosecond timestamps, gaps like +59m60s, sorting lines
  with Windows line endings, and Copy buttons when the clipboard is blocked.
• The popup's text box is kept in memory only (chrome.storage.session) instead of localStorage.