Add Apple xctrace CPU profiling under perf #697

Parent

#694

What to build

Add Apple native CPU profiling under the consolidated perf family. This issue groups Apple xctrace work because active app process resolution, xctrace invocation, retry behavior, export/report handling, and device/simulator support all share the same platform seams.

Prototype CLI shape:

agent-device perf cpu profile start --kind xctrace --template "Time Profiler" --out app.trace
agent-device perf cpu profile stop --kind xctrace --out app.trace
agent-device perf cpu profile report --kind xctrace --out app-profile.json
agent-device perf trace start --kind xctrace --template "Animation Hitches" --out hitches.trace
agent-device perf trace stop --kind xctrace --out hitches.trace

Expected agent experience:

• Agents first run perf metrics or perf frames to confirm native/device slowness.
• Agents escalate to xctrace CPU profiling when logs and quick metrics do not identify the cause.
• Existing perf xctrace Activity Monitor and Animation Hitches behavior should inform hints and retry behavior, but profiler artifacts must be returned as paths plus compact summaries.

Acceptance criteria

• Active Apple app sessions can resolve the target app process for xctrace profiling.
• perf cpu profile start|stop --kind xctrace captures a bounded .trace artifact for the active app when supported.
• perf cpu profile report --kind xctrace returns a compact report when xctrace export can provide useful data.
• The support matrix clearly distinguishes physical iOS device, iOS simulator, and macOS behavior.
• Existing iOS device xctrace retry and actionable hint patterns are reused where practical.
• Commands return artifact paths and metadata, not full trace contents.
• dSYM/symbolication is not bundled into this issue unless it is required for the compact profiler report; broader symbolication remains in the debug symbols issue.

Validation

• iOS platform unit tests with mocked xcrun xctrace record and xcrun xctrace export.
• Session handler tests for command routing and unavailable target hints.
• pnpm check:unit
• pnpm format

Blocked by

• Add perf metrics and frames subcommands as native diagnostics foundation #695