Fix earn demo borrow/withdraw/swap issues

[its-everdred]

Fixes for the Aave/Uniswap earn demo (packages/demo/frontend). 112 tests, lint, build green. No backend changes.

• Repay-max revert + raw error leak — repaying max USDC reverted with "ERC20: transfer amount exceeds balance" (the repay gate read the cross-chain total, but USDC_DEMO sits on both Base + OP Sepolia, so max prefilled more than the borrow chain could spend), and the raw revert calldata leaked into the modal. Fix: scope the gate to the market's chain; show ActionsError.shortMessage.
• Health bar overshoot — after a successful borrow the utilization bar shot to ~100% before settling to ~60%, because the optimistic position update landed (debt now includes the borrow) while the form amount was still set, double-counting it. Fix: zero the projected delta while the tx executes.
• Withdraw "You withdraw 0" — the withdraw review modal showed 0 when withdrawing 0.0001, because it rendered the raw amount state (empty when the illiquid Aave amount is locked) instead of the effective amount. Fix: use effectiveAmount, and feed it to the health projection too.
• Testnet withdraw error — illiquid Aave ETH withdrawals can revert on low testnet liquidity but only showed "Transaction failed". Fix: surface a testnet-specific message for that market+mode.
• Balance flicker $70→$140→$70 — switching to the Borrow tab auto-pledges the lent Morpho shares; the pledged collateral landed (optimistic) before the direct lend shares refetched to zero, so the same shares were summed twice. Fix: the reconcile moves direct→pledged in one optimistic update, and buildEffectiveLendPositions reads it as a fallback so the total never double-counts.
• Swap revert — USDC→OP Uniswap swaps sometimes reverted with only "tx failed". Pool/fee/liquidity check out, so it's a runtime revert needing an on-chain repro; pinned pending one. The swap now surfaces the real reason instead of "tx failed".

Also: mise.toml [alias]→[tool_alias].

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