Finish Folder Studio size target followups

[shiny-code-bot]

Summary

• Make first soft size targets remain measurement-first, while confirmed measured follow-ups can carry a learned max-encoded-percent ceiling after an over-target sample.
• Add measured_size_followup to the operator note parse contract and preserve nested size-budget request state for combined experiments.
• Turn Folder Studio's Revise smaller action into a measured-context prompt that focuses the bench composer without erasing an existing draft note.

Verification

• uv run --with pytest pytest -q tests/test_tuning_runtime.py
• npm --prefix frontend run test:unit -- --run src/lib/components/workstation/folder-studio-view.test.ts
• Browser validation on /folders/tv/Overshoot%20Show/Season%201 using the web-smoke fixture, including empty composer prefill and existing-note append behavior.
• uv run /Users/cbusillo/Developer/codex-skills/jetbrains-inspection/scripts/jb-inspect.py closeout --repo /Users/cbusillo/Developer/mediaforce --scope changed_files
• bash scripts/pre-commit-check.sh

Notes

• The first acceptance-gate attempt failed because a manually started web-smoke server was still running under its lock; after stopping the orphaned process, standalone npm --prefix frontend run smoke:web and the full acceptance gate passed.