Close the gaps an audit of courses, tasks, files and grades turned up

Every area — courses, rooms, boards, topics, tasks, files, quizzes, teams,
groups, submissions, grades — was checked for data the instance has and the
tools did not show.

Grades and feedback. A teacher's /homework page is a different page from a
student's: grade and comment live in the grading form, one block per
submission, so a teacher account reported every graded submission as having
neither. parseTeacherGrading reads the form, and list_submissions can now
include the written feedback and who handed the work in.

Names. /api/v1 is partly served: courses, users and classes survive in the
deployment's ingress table, and users/{id} is the only route from an id to a
name. Submitters, file creators and course teachers resolve through it, and
degrade to "not visible to this account" where a student may not read them.

Courses, rooms and classes. get_course adds the description, teachers,
member count and weekly timetable from /api/v1/courses. list_classes is new.
get_room reports what the account may do — allowedOperations is an object of
booleans, not the list it was typed as — and applicants and invitation links
where it may manage them.

Board and topic content. Link descriptions, image alt text, drawing and
video-conference titles, the ids behind external tools and H5P content (the
only thing resembling a quiz), and what a deleted element used to be. Topic
Etherpad pads are read like board pads, and htmlToText keeps table columns
apart and drops template indentation.

Files. A scan with no text layer falls back to the preview endpoint, whose
width and outputFormat are undocumented enums, so Claude gets a picture of
the page; list_files reports counts and sizes. Teams stay documented as
unreadable at any API version; their files come later.

What the crawl missed. Tasks attached to topics (18 of 60 on the live
account), each course's own file area, and — behind INDEX_PERSONAL_FILES —
personal files and submissions with their grade comments, so search and
what_changed cover grading. A submission hit points at get_task.

The local instance's preview profile gets an ImageMagick policy that allows
the coders its 7.1.2 build needs; the image's own denies them all.

110 tests.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.env.example

@@ -42,6 +42,12 @@ DATABASE_URL=postgresql://schulcloud:schulcloud@postgres:5432/schulcloud
 # still downloadable, proxied live. Default 64 MiB.
 # MIRROR_MAX_BYTES=67108864
 
+# Also index personal files ("Meine Dateien") and submitted / returned work,
+# including teacher grade comments. This is what makes "what did the teacher
+# say about X" searchable and lets what_changed report a re-grade. Costs roughly
+# three extra requests per task on a full crawl, so it is off by default.
+# INDEX_PERSONAL_FILES=false
+
 # How often to re-crawl on a timer, in ms. Default 21600000 (6h). 0 = on demand
 # only. A re-crawl of unchanged content downloads nothing, because Schulcloud
 # file records are immutable.