Handle moving average updates on candle revisions

[qqrm]

Summary

• Added SMA/EMA replacement helpers so MovingAverageEngine can adjust window sums and last EMA when the latest close is revised in place.【F:src/domain/market_data/indicator_engine.rs#L83-L201】
• Taught Chart::add_realtime_candle and aggregate updates to detect timestamp-equal candles and invoke the replacement path, keeping indicators in sync during partial updates.【F:src/domain/chart/entities.rs#L100-L225】
• Added a wasm-bindgen integration test that feeds repeated real-time closes and checks that SMA/EMA settle on the final value for base and aggregated intervals.【F:tests/moving_average_updates.rs#L1-L50】

Testing

• cargo fmt --all
• cargo check --tests --benches
• cargo clippy --tests --benches --fix --allow-dirty -- -D warnings
• cargo test (fails: wasm-bindgen UI tests panic at src/app.rs:1421 because DOM-dependent setup is unavailable in the harness)
• CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUNNER=wasm-bindgen-test-runner cargo test (fails with the same DOM-dependent wasm tests)

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https://chatgpt.com/codex/tasks/task_e_68cb93d1c11c833291d91f13e9989453