* fix: add MFS operation limit for --flush=false
adds a global counter that tracks consecutive MFS operations performed
with --flush=false and fails with clear error after limit is reached.
this prevents unbounded memory growth while avoiding the data corruption
risks of auto-flushing.
- adds Internal.MFSNoFlushLimit config
- operations fail with actionable error at limit
- counter resets on successful flush or any --flush=true operation
- operations with --flush=true reset and don't count
this commit removes automatic flush from https://github.com/ipfs/kubo/pull/10971
and instead errors to encourage users of --flush=false to develop a habit
of calling 'ipfs files flush' periodically.
boxo will no longer auto-flush (https://github.com/ipfs/boxo/pull/1041) to
avoid corruption issues, and kubo applies the limit to 'ipfs files' commands
instead.
closes#10842
* test: add tests for MFSNoFlushLimit
tests verify the new Internal.MFSNoFlushLimit config option:
- default limit of 256 operations
- custom limit configuration
- counter reset on flush=true
- counter reset on explicit flush command
- limit=0 disables the feature
- multiple MFS command types count towards limit
* docs: explain why MFS operations fail instead of auto-flushing
addresses feedback from https://github.com/ipfs/kubo/pull/10985#pullrequestreview-3256250970
- clarify that automatic flushing at limit was considered but rejected
- explain the data corruption risks of auto-flushing
- guide users who want auto-flush to use --flush=true (default)
- document benefits of explicit failure for batch operations
(cherry picked from commit a688b7eeac)