fix: replace modal workspace confirmation

[silversurfer562]

Outcome

Consequential workspace actions no longer depend on browser modal dialogs, which are unavailable in sandboxed MCP App hosts.

Behavior

• first click arms and relabels the action without submitting
• second click submits the authority-bound payload with confirmed=true
• choosing another action disarms and restores the pending action
• prepares attune-forms 0.11.1

Receipts

• python -m pytest -p no:cacheprovider -q — 889 passed
• python -m ruff check src tests — passed
• python -m build — built 0.11.1 sdist and wheel
• attune-ai Fix integration probes against this source — 62 passed

Parallel PR check

PR #60 overlaps only CHANGELOG.md and changes bridge re-exports, not workspace action behavior.