Normalize OCC option symbols from broker sync to compact format

[triantos]

Summary

• Brokers (via SnapTrade) may return space-padded OCC symbols (e.g. GE 270115C00340000) which creates duplicate assets when the same contract also appears in compact form (GE270115C00340000)
• Parse incoming option symbols in the broker mapping layer with the existing parse_occ_symbol() utility and rebuild in compact format via build_occ_symbol() to ensure consistent asset identity

Test plan

• Verify existing option positions from Connect sync are not duplicated
• Verify option symbols from non-Connect sources (CSV import, manual entry) are unaffected
• All existing tests pass

[afadil]

[P2] Option symbol normalization is already handled downstream

This looks redundant now.
Option symbol normalization is already happening in the current sync path: option positions are normalized in broker sync, and activity symbols are normalized again when prepare_activities_for_sync() builds the asset spec. That means asset identity is already canonicalized before instrument_key generation, so doing another normalization here does not fix a missing case in the final path.

If we keep any normalization at this layer, it should call the shared normalize_option_symbol() helper rather than duplicating parse/rebuild logic, otherwise this can drift from the canonical path and miss broker-specific compact formats.



**[P1] Metal weight is dropped during pricing
I don’t think the metal change is safe to merge as written.**



Normalizing XAU-500G / XAU-1KG to XAU fixes provider lookup, but it also changes the pricing unit to a 1 oz spot quote. The valuation path still uses quantity * price * contract_multiplier, and contract_multiplier() is 1 for metals, so metal_weight_oz() is never applied anywhere. As a result, one XAU-500G holding would now be valued as one ounce of gold instead of ~16.0754 oz.

So I agree with normalizing for provider lookup, but we also need a weight-aware adjustment before merging this, for example by scaling latest/historical metal quotes by metal_weight_oz() (or otherwise carrying the weight through valuation).

[triantos]

Re option normalization: OK, yes this is no longer needed now that you've merged my other change and normalize_option_symbol().

On the topic of metals, this got lost during one of my refactors. Sorry. I have fixed with an updated [trivial] commit.