feat(cli): migrate flow-run command to cyclopts (wave 3b)

[zzstoatzz]

Native cyclopts implementation of all flow-run subcommands, replacing the delegation stub that forwarded to typer.

flow-run is an atomic unit — once registered as a native app, all subcommands must exist — so this includes all 7 commands in one PR (635 LOC, above the usual 500 target).

What changed

• New: src/prefect/cli/_cyclopts/flow_run.py — inspect, ls, delete, cancel, retry, logs, execute + _get_flow_run_by_id_or_name helper
• Wiring: replaced delegated stub with native import, removed "flow-run" from _DELEGATED_COMMANDS, added to _CYCLOPTS_COMMANDS
• Tests: mock_webbrowser fixture patches webbrowser.open_new_tab on the module directly (works for both import paths); delete uses prefect.cli._prompts.confirm instead of typer.confirm
• Gotcha: flow_run_app uses version_flags=[], help_flags=["--help"] to prevent flag interception

Test plan

• uv run pytest tests/cli/test_flow_run.py — 73 passed, 1 skipped (typer)
• PREFECT_CLI_FAST=1 uv run pytest tests/cli/test_flow_run.py — 73 passed, 1 skipped (cyclopts)
• uv run pytest tests/cli/test_cyclopts_parity.py — 18 passed
• ruff clean

🤖 Generated with Claude Code

[codspeed-hq]

Merging this PR will not alter performance

✅ 2 untouched benchmarks

---

_{Comparing cli-cyclopts/wave-3b (4219809) with main (5b81df1)}