[AndyScherzinger]

FreeMind (.mm) files did not open: the editor showed "Load file fail!ReferenceError: FilesMindMap is not defined", although the app lists FreeMind as supported (read-only). Testing with real files then showed more gaps in the import. One commit each:

• Load failure: src/plugins/freemind.js still called xml2json through a global FilesMindMap.Util. That global no longer exists since the frontend was split into modules in November 2024 (62f4fe1), so every .mm file failed in every release since. The plugin now imports util as the XMind plugin does. The unit test defined that global itself, which hid the problem; it now tests the real module.
• Formatted text (FreeMind 0.9 and later): text with any formatting is stored as HTML in <richcontent TYPE="NODE"> instead of the TEXT attribute. Such nodes, often the central one, were empty; their text is now taken from the HTML, one line per paragraph.
• Line breaks: <br> in that HTML is now a line break, while the whitespace the HTML is wrapped with is still collapsed.
• Formatted text (FreeMind 0.8): that version stored the HTML directly in TEXT, which showed up as raw markup. It is now converted the same way. Form fields in it, such as rating dropdowns, show their chosen value.
• Notes and folded branches: notes (<richcontent TYPE="NOTE">) now become editor notes, and branches folded in FreeMind (FOLDED="true") open collapsed.
• Icons: FreeMind icons the editor has no marker for are shown as emoji before the node text (✅, ⌛, 😊, ℹ️, …), so icon-only nodes are no longer empty. full-9 now maps to priority 9 like full-1 to full-8.
• Images: a node whose formatted text is just an image gets the image's alt text or file name as its text (binah.gif → "binah"), and an image on the web becomes the node's link unless it has one already. Images themselves can't be shown: external ones are blocked by the CSP.
• Text style and colours: a node's bold, italic, size and font name (<font>), its text colour (COLOR) and its background (BACKGROUND_COLOR) are taken over. FreeMind's default font (SansSerif, Dialog) is left to the editor, Java's other logical fonts map to CSS families, and a node with a background but no text colour gets FreeMind's black text. Branch line colours and styles (<edge>) have no counterpart and stay unmapped.
• Not a FreeMind file: a .mm file without a FreeMind map, such as a saved web page, failed with a TypeError about reading TEXT of undefined. It now fails with "This file is not a valid FreeMind mind map.". Decoding errors reach the alert as their message instead of the error object.

Tested on Nextcloud 32, 35 and 36, in Chromium and Firefox, with the same results on every version and in both browsers:

File	Nodes	Central node	Notes	Collapsed
FreeMind template (FreeMind 1.1)	290	"FreeMind / Mind Map / Template"	–	4
FreeMind's own documentation map (1.0.1)	482	"FreeMind / - free mind mapping software -"	17	58
Freeplane "Basic Functions" map (Freeplane 1.9)	69	"Basic Freeplane / Functions"	34	–
A FreeMind 0.8 map	137	"Complete Man"	–	40
A saved web page named .mm	–	clear error message	–	–

The counts match the files. After the icon and image commits, no node is empty except two with TEXT="" in the Freeplane file. In Windows Chrome the emoji render in colour, for example "✅ DONE" and "✅😊 Done, but improvements possible" in the template; its central node keeps its green background with black text, and the "RESULT" nodes of the 0.8 map are red, bold and italic as in FreeMind. Unit tests cover each case; Vitest and lint pass.

Backport: #408.

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI (N/A)