feat: Enable custom query condition in snapshot mode (#51)

[ardakyigit]

• Add QueryCondition to SnapshotConfig and publication.Table
• Update all snapshot query builders to inject custom conditions
• Per-table conditions take precedence over global conditions

Fixes #51

[Abdulsametileri]

• Could you fix pipeline errors?
• Could you write integration test?
• Could you also put a example for this new feature and add documentation about it [docs/SNAPSHOT_FEATURE.md] and README.md

[Abdulsametileri]

# Global condition - applies to all tables
snapshot:
  enabled: true
  mode: initial
  queryCondition: "is_active = true"  # Only snapshot active records

# Per-table override - takes precedence
publication:
  tables:
    - name: users
      schema: public
      queryCondition: "created_at > '2024-01-01'"  # Recent users only
    - name: orders
      schema: public
      # Uses global condition (is_active = true) 
    - name: archived_data
      schema: public
      queryCondition: "1=1"  # Override: snapshot all rows

it works like that?

[Abdulsametileri]

We can add omitempty this too because you already did it on https://github.com/Trendyol/go-pq-cdc/pull/80/changes#diff-0d5f530c672480426b61bfb1ac0f072aadc34cfb1c50c816653dc714f2f83206R41

[Abdulsametileri]

getQueryCondition methods takes tableSchema as the first parameter, you also define it here.

We can rename it tblSchema and use it in the for.

 tblSchema := table.Schema  // Farklı isim, karışıklık yok
    if tblSchema == "" {
        tblSchema = "public"
    }

[sunziping2016]

I happened to see this PR and tried it. However, I found per-table QueryCondition not working.

Probably, the s.tables is synthesised from the PGSQL queries and user-provide config. And the synthesizing code is missing in the locations shown below.

go-pq-cdc/config/config.go

Lines 262 to 264 in 7a137ba

	if userTable.SnapshotPartitionStrategy != "" {
	result[i].SnapshotPartitionStrategy = userTable.SnapshotPartitionStrategy
	}

go-pq-cdc/config/config.go

Lines 179 to 181 in 7a137ba

	if st.SnapshotPartitionStrategy != "" {
	mergedTable.SnapshotPartitionStrategy = st.SnapshotPartitionStrategy
	}