Disable automated CI triggers; run iOS Maestro E2E on Linux via sim-remote

[jwajgelt]

Summary:

Two infrastructure changes for this fork:

1. Remove automated workflow triggers. This fork doesn't need upstream's CI automation. All push, pull_request/pull_request_target, schedule, issues/issue_comment, and release triggers are replaced with workflow_dispatch, so nothing runs automatically but every workflow can still be run by hand. Reusable workflow_call workflows (only runnable from a dispatched workflow) are untouched.

2. Run the iOS Maestro E2E tests on Linux against remote simulators. The E2E jobs move from macOS runners to ubuntu-latest, driving a remote fleet simulator through sim-remote (softu release, which includes the Maestro shims from software-mansion/radon-cloud#143):

• .github/actions/maestro-ios: installs libplist-utils (backs the plutil shim), downloads the arch-matched sim-remote binary, sim-remote login to acquire a fleet machine (with a guard so an unset SIM_ROUTER_URL secret doesn't override the baked-in router URL), eval "$(sim-remote install-shims)" before running Maestro, and sim-remote logout on always().
• maestro-ios.js: uses explicit UDIDs instead of the booted alias (which only resolves locally), opens a sim-remote reverse start <udid> 8081 tunnel in Debug so the app in the remote simulator can reach the runner-local Metro, and falls back from "iPhone … Pro" to any iPhone when picking a device.
• e2e-ios-rntester.yml: test job moves to ubuntu-latest (the .app is built upstream and downloaded as an artifact).
• e2e-ios-templateapp.yml: split into a macOS build job (init project, pod install, xcodebuild, upload .app artifact) and a Linux test job (download .app, re-init the project JS-only for Metro in Debug, run Maestro).

Reviewer notes:

• Running the E2E requires the SIM_ROUTER_USERNAME / SIM_ROUTER_API_KEY repo secrets (SIM_ROUTER_URL optional — a default is baked into the binary).
• Each matrix flavor (and each retry in test-all.yml) acquires its own fleet machine; queueing is bounded by the 900 s login timeout.
• Video recording depends on SIGINT reaching the recording shim to finalize the .mov; if flaky, the artifact step simply uploads whatever files exist.

Changelog:

[INTERNAL] [CHANGED] - Disable automated CI triggers on this fork and run iOS Maestro E2E on Linux runners via sim-remote

Test Plan:

• python3 -c "yaml.safe_load(...)" over every touched workflow/action file — all parse.
• node --check .github/workflow-scripts/maestro-ios.js — passes. (ESLint not run: no node_modules in the worktree.)
• On a Linux (aarch64) VM: downloaded the softu sim-remote binary with the exact commands the action uses; verified install-shims, login, logout, reverse start <UDID> <PORT>, and simctl passthrough all exist; eval "$(sim-remote install-shims)" puts all six shims (xcrun, xcodebuild, plutil, applesimutils, open, xcode-select) on PATH and exports SIM_REMOTE_BIN; plistutil is provided by libplist-utils.
• Not run: a full E2E pass against an actual fleet machine (needs the router secrets configured on the repo).