docs(qa): record file-chooser suite-sweep report

[wmfeht]

Description

Adds the strata-qa-file-chooser sweep report for wmfeht/strata @ 66fb0e6 (v0.15.0) at working-docs/qa-suite-sweep-20260911/qa/file-chooser.md.

Dedicated-client portal paths (OpenFile / SaveFile / SaveFiles, version 4, filters, views, remote-URI error, new folder, preview) hold. Verdict is pass-with-nits: known lgse/strata#717 still fails in the GTK filter; four ignored xdotool tests failed when run alone (harness-sensitive, not filed). No product code changes, no issues filed, no product PR comments.

Origin wmfeht/strata-skills (COMMON.md, strata-qa-file-chooser/SKILL.md) was not readable from this VM; cases follow docs/portal-file-chooser.md and sibling sweep layout.

Visual evidence

QA session captures (private Xvfb :99, never DISPLAY=:1):

OpenFile filter hit notes.txt
SaveFile replace-existing confirmation
SaveFiles multi overwrite confirmation
40-filter list opens with Filter 01
Remote URI local-only error
Ctrl+Shift+N inline new folder
Space preview of sample.png
List view Classic Light

How to test

1. Read working-docs/qa-suite-sweep-20260911/qa/file-chooser.md.
2. Optional replay (private Xvfb + throwaway XDG, never the Cloud desktop display):

cargo build --bin strata --locked
python3 scripts/portal-test.py single --binary target/debug/strata
python3 scripts/portal-test.py save --binary target/debug/strata --choices
python3 scripts/portal-test.py savefiles --binary target/debug/strata --choices

Expected result: dedicated client prints response 0 on accept and 1 on cancel; the report matches the D-Bus JSON and screenshots under /opt/cursor/artifacts.

Related issue

N/A — documentation-only QA sweep report. Known lgse#717 is already open; this PR does not close or file issues.

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