PR 14044: Linux reveal selection
Base: 1451e7cb23034d29774338608368a15d8845df36
Head: 5af2779258316ddceb5975b0fc1f7f5d89f34970

Focused suite: original 61 registered -> takeover 63 registered (61 pass, 2 Windows-only skips); main 58 registered. Both selection regressions fail against exact main. Server typecheck, targeted lint and format pass.

BEFORE (exact main production):
{"mode":"selected","dbusCalls":[],"fallback":{"args":["/tmp/t3-reveal-proof-09-SYNTHETIC/media"],"helperAlive":false},"elapsedMs":105}
node:internal/modules/run_main:107
    triggerUncaughtException(
    ^

AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:

0 !== 1

    at file:///tmp/ssh-relay-remote-09/14044-process-proof.mjs:36:33 {
  generatedMessage: true,
  code: 'ERR_ASSERTION',
  actual: 0,
  expected: 1,
  operator: 'strictEqual',
  diff: 'simple'
}

Node.js v24.21.0

AFTER (exact head production):
{"mode":"selected","dbusCalls":[{"method":"ShowItems","uris":["file:///tmp/t3-reveal-proof-09-SYNTHETIC/media/a%20'quoted'%20%22clip%22%20%23100%25%20%3F%20%C3%A9%5Cname.mp4"],"startupId":""}],"fallback":null,"elapsedMs":44}
{"mode":"rejected","dbusCalls":[{"method":"ShowItems","uris":["file:///tmp/t3-reveal-proof-09-SYNTHETIC/media/a%20'quoted'%20%22clip%22%20%23100%25%20%3F%20%C3%A9%5Cname.mp4"],"startupId":""}],"fallback":{"args":["/tmp/t3-reveal-proof-09-SYNTHETIC/media"],"helperAlive":false},"elapsedMs":93}
{"mode":"stalled","dbusCalls":[],"fallback":{"args":["/tmp/t3-reveal-proof-09-SYNTHETIC/media"],"helperAlive":false},"elapsedMs":3054}
{"mode":"cancelled","dbusCalls":[],"fallback":null,"elapsedMs":1045}
PASS: real private-session FileManager1 URI selection, rejected-call fallback, SIGTERM-resistant helper termination before fallback, and external-cancellation cleanup.

Uses production ExternalLauncher, actual gdbus, private D-Bus session and a FileManager1 protocol fixture. Tests URI delivery, rejection fallback, SIGTERM-resistant helper cleanup before fallback and external cancellation. No graphical file manager was launched. Actual Nautilus/Dolphin selection, WSLg, macOS, Windows, Electron and mobile remain unverified.