fix(app): stabilize tool stream lifecycle

[fschrhunt]

Summary

• Track active tool/plugin calls by call id so overlapping control calls stay truthful
• Split plugin summaries by surface and finalize them on run end/error/abort
• Remove launch-time Safari permission priming and restore the composer session picker
• Add regressions for media paste, plugin lifecycle, and mixed plugin rows

Verification

• swift test
• ./script/build_and_run.sh --verify

Risks

• Stream row copy changed from ended to neutral/finished/stopped states.