feat!: replace Abiword with LibreOffice and add DOCX export (#7539)

* feat!: replace Abiword with LibreOffice and add DOCX export (#4805)

The Abiword converter is dropped. Abiword's DOCX export is weak and the
project is niche on modern platforms; LibreOffice (soffice) is the
common deployment path and now serves as the sole converter backend.

DOCX is added as an export format and becomes the new target for the
"Microsoft Word" UI button. The /export/doc URL still works for legacy
API consumers.

BREAKING CHANGE: The 'abiword' setting, the INSTALL_ABIWORD Dockerfile
build arg, the abiwordAvailable clientVar, and the
#importmessageabiword UI element (with locale key
pad.importExport.abiword.innerHTML) are removed. Deployments relying on
Abiword must configure 'soffice' instead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* feat: add docxExport feature flag and abiword deprecation WARN

- Add `docxExport: true` setting to opt out of DOCX (use legacy DOC)
- Pass `docxExport` to client via clientVars
- Use `docxExport` flag in pad_impexp.ts for Word button format
- Emit a specific WARN when deprecated `abiword` config is detected
- Update settings.json.template and settings.json.docker with docxExport
- Add docxExport to ClientVarPayload type in SocketIOMessage.ts

Agent-Logs-Url: https://github.com/ether/etherpad/sessions/9afc5291-73b2-4b66-b028-feed39e7056f

Co-authored-by: JohnMcLear <220864+JohnMcLear@users.noreply.github.com>

* refactor: extract wordFormat variable and improve docxExport comment

Agent-Logs-Url: https://github.com/ether/etherpad/sessions/9afc5291-73b2-4b66-b028-feed39e7056f

Co-authored-by: JohnMcLear <220864+JohnMcLear@users.noreply.github.com>

* fix: restore import-limitation message when no converter is configured

The abiword removal dropped both the #importmessageabiword DOM element
and its locale key, but Copilot's refactor still expected the show()
call to surface a message when exportAvailable === 'no'. Result: users
with no soffice binary got silent failure instead of an explanation.

Add #importmessagenoconverter back with updated, LibreOffice-focused
copy (new locale key pad.importExport.noConverter.innerHTML) and flip
the hidden prop when the client knows no converter is available.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* i18n: inline English fallback for noConverter import message

The original abiword message existed in ~70 locale files and was
removed from all of them by this PR. The replacement key was only
added to en.json, so non-English users had an empty div until
translators localize. Follow the project's usual pad.html pattern
(e.g. line 146's "Font type:") and include the English text inside
the div as the fallback content; html10n replaces it when a
translation is available.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Revert "i18n: inline English fallback for noConverter import message"

This reverts commit f336f24d. Follow the project convention: add the
new locale key to en.json only and let translations catch up via the
translation system, rather than putting inline fallback in the template.

* i18n: leave non-English locale files untouched

The PR had removed pad.importExport.abiword.innerHTML from ~82 locale
files alongside its removal from en.json. The replacement message uses
a new key (pad.importExport.noConverter.innerHTML) in en.json only, so
churning every localisation file for a key that is no longer referenced
produces useless translation diffs. Restore every non-en locale file to
its pre-PR state.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: JohnMcLear <220864+JohnMcLear@users.noreply.github.com>

settings.json.docker

@@ -91,7 +91,7 @@
  *    "password": "${PASSW:}" // if PASSW is not defined would result in password === ''
  *
  *    If you want to use an empty value (null) as default value for a variable,
- *    simply do not set it, without putting any colons: "${ABIWORD}".
+ *    simply do not set it, without putting any colons: "${SOFFICE}".
  *
  * 3) if you want to use newlines in the default value of a string parameter,
  *    use "\n" as usual.
@@ -348,25 +348,23 @@
    */
   "maxAge": "${MAX_AGE:21600}", // 60 * 60 * 6 = 6 hours
 
-  /*
-   * Absolute path to the Abiword executable.
-   *
-   * Abiword is needed to get advanced import/export features of pads. Setting
-   * it to null disables Abiword and will only allow plain text and HTML
-   * import/exports.
-   */
-  "abiword": "${ABIWORD:null}",
-
   /*
    * This is the absolute path to the soffice executable.
    *
-   * LibreOffice can be used in lieu of Abiword to export pads.
-   * Setting it to null disables LibreOffice exporting.
+   * LibreOffice is used for advanced import/export of pads (docx, pdf, odt).
+   * Setting it to null disables LibreOffice and will only allow plain text
+   * and HTML import/exports.
    */
   "soffice": "${SOFFICE:null}",
 
   /*
-   * Allow import of file types other than the supported ones:
+   * When true (the default), the "Microsoft Word" export button downloads a .docx file via
+   * LibreOffice (requires "soffice" to be set). Set to false to revert to legacy .doc output
+   * (which also requires "soffice").
+   */
+  "docxExport": "${DOCX_EXPORT:true}",
+
+  /*
    * txt, doc, docx, rtf, odt, html & htm
    */
   "allowUnknownFileEnds": "${ALLOW_UNKNOWN_FILE_ENDS:true}",