Repo root is full of untracked scratch/junk files

Observed 2026-07-29, pre-existing (not from any one session's work). git status on the
opencv5 working branch shows ~50 untracked files/dirs at the repo root and scattered through
src/, docs/, examples/, tests/, e.g.: stray scratch scripts (findimages.py,
phone.py, sunday.py, readbag.py, fmtparser.py, audit_typing.py, inspect_bag.py,
src/machinevisiontoolbox/cvfuncs.py, docbugs.py, newcameras.py, test_skimage.py,
testblobplots.py), planning notes (CODEAUTOLINK_FORK_PLAN.md, MIGRATION.md, NOTES,
OPENCV_FUNCTIONS.md/OPENCV_FUNCTIONS-original.md, plot_call_inventory.md), build
artifacts (machinevision-toolbox-python.pdf/.svg, machinevisiontoolbox.pdf,
aruco0.pdf, aruco50.pdf), stray media/data (flowers.jpg, xx.mp4, ss, bags/,
examples/bus.jpg, examples/street_scene.jpg, examples/yolo26n.pt,
packages/mvtb-data/mvtbdata/data/bunny.dat, .../images/tags.png), old Sphinx warning-log
captures (docs/warnings*.txt), and a couple of loose x.json files.

One item worth checking rather than just sweeping up: release-please-config.json is
untracked despite release-please.yml requiring it (config-file: release-please-config.json) — if that's really never been committed, release-please may
only be working by accident (whatever's on disk locally) and would break for anyone else's
checkout / a fresh CI runner. Worth confirming before cleanup, not after.

Fix

Triage into: (a) delete outright (build artifacts, one-off scratch scripts that are clearly
done), (b) commit properly if still wanted (release-please-config.json almost certainly
belongs in git), (c) move to .gitignore if it's a recurring local-only output (e.g. the
docs/warnings*.txt capture files, if that workflow continues). Don't bulk git clean -xdf
without a human eyeballing the list first — some of this may be in-progress work, not junk.

Start by reviewing the git status list and the named scratch files, notes, artifacts, media, and warning logs, without running a bulk cleanup. Check release-please.yml against the untracked release-please-config.json, then triage items for deletion, committing, or .gitignore. Done means intended work is preserved, recurring local outputs are handled, and the release configuration works from a fresh checkout.