Mobile GUI effort slider doesn't reflect actual session effort level on open

Same Claude Code session accessed via CLI and the mobile app.

Steps to reproduce:
1. Open mobile GUI's effort control on a session already in progress
2. Slider/label showed "High"

Expected: the effort control should read and display the session's true
current effort level on open, not a possibly stale/default value.

Actual: showed "High" — not confirmed to match the session's actual
current effort setting at that moment.

After manually setting the slider to Medium, it correctly updated and
displayed Medium going forward.

Note: I can't confirm from the CLI side what the session's true effort
value was at the moment the GUI first opened — flagging this as a
potential bug rather than confirmed, since the mismatch on initial
load wasn't independently verified against backend state.

Reproduce the session-sharing case by opening the mobile effort control on an in-progress session and compare the initial slider and label with the session's current CLI or backend effort value. Confirm whether the initial display is stale or defaulted, then verify that opening the control reflects the true current level while manual changes continue to update correctly.

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