[Bug Report] eQSL Export Missing GRIDSQUARE Field

[KI7MT]

Bug Description

eQSL ADIF exports do not include MY_GRIDSQUARE or GRIDSQUARE fields, making them unusable for IONIS validation.

Steps to Reproduce

1. Export ADIF from eQSL inbox
2. Run ionis-validate adif validate ki7mt-eqsl-inbox.adi
3. Observe: 0 valid HF QSOs found despite 23,877 records

Expected Behavior

ADIF export should include grid locator fields for both stations.

Actual Behavior

| Records | 23,877 |
| Valid HF | **0** |
| Issue | No GRIDSQUARE field in export |

System Info

ionis-validate	v0.2.3
Device	mps
OS	Darwin 25.2.0

Suggested Resolution

1. Document eQSL limitation in README
2. Add clear error message when ADIF lacks grid fields
3. Consider callsign→grid lookup as fallback (using Rosetta Stone)

Workaround

Use LoTW or QRZ exports instead — both include grid fields.

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Note: This is an upstream data source limitation, not an ionis-validate bug.