chore(thunderbird): switch flatpak app id to org.mozilla.thunderbird

Upstream marked org.mozilla.Thunderbird end-of-life. Flathub split it
into two replacement IDs:

  org.mozilla.thunderbird      monthly release channel (new default)
  org.mozilla.thunderbird_esr  ESR / long-term-support channel

Move to the lowercase monthly-release flatpak, which is what Mozilla
now recommends for regular desktop users and gets features at the same
cadence as Firefox.

Renamed references in:

* meta/flatpak.txt          - the package list the user installs from
* meta/base.txt             - comment in the mail-bits section
* dot_config/sway/config    - window-match app_id rule for marking
* dot_config/mimeapps.list  - mailto/ics/webcal handler .desktop names
* run_onchange_after_deploy-thunderbird.sh.tmpl - profile path under
  ~/.var/app/<id>/.thunderbird/
* run_onchange_after_deploy-tb-eer.sh.tmpl - flatpak override target
  and sandbox path for External Editor Revived bridge
* run_onchange_after_deploy-pteid-pkcs11.sh.tmpl - Mozilla-family
  flatpak NSS DB registration list
* README.md                 - doc snippets and xdg-mime example

On-host migration:

  flatpak install -y flathub org.mozilla.thunderbird
  # Preserve accounts, OpenPGP keys, calendars, EER bridge wrapper:
  mv ~/.var/app/org.mozilla.Thunderbird ~/.var/app/org.mozilla.thunderbird
  flatpak uninstall -y org.mozilla.Thunderbird
  chezmoi apply -v
  update-desktop-database ~/.local/share/applications 2>/dev/null || true

Verify mail handler:
  xdg-mime query default x-scheme-handler/mailto
  # -> org.mozilla.thunderbird.desktop

0 files changed, 0 insertions, 0 deletions