[explorer/puller] fix: widen symbol_blocks.total_fee to bigint to avoid overflow

[daoka]

Problem

symbol_blocks.total_fee was defined as int (PostgreSQL integer, max ~2.1B). Live-node validation against testnet (https://401-sai-dual.symboltest.net:3001) found a real block (height 6224) with totalFee = 13199992608, which exceeds that range and made upsert_blocks fail with psycopg2.errors.NumericValueOutOfRange.

total_fee sums fees across every transaction in a block, so unlike per-transaction fee fields it can plausibly exceed int4 on a block with many/large-fee transactions.

Solution

Widen total_fee to bigint, matching the existing difficulty/total_voting_balance columns.

Test plan

• test_create_tables_creates_symbol_block_columns_and_constraints updated to expect int8
• New regression test test_can_upsert_block_when_total_fee_exceeds_int4, using the real observed value (height 6224, 13199992608)
• cd explorer/puller && PYTHONPATH=.:.. python -m pytest tests/ -v — 231 passed
• bash scripts/ci/lint.sh — 10.00/10
• 100% patch coverage on changed lines

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.15%. Comparing base (663f4b9) to head (5c13f26).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #2389   +/-   ##
=======================================
  Coverage   97.15%   97.15%           
=======================================
  Files         289      289           
  Lines       22381    22381           
  Branches      206      206           
=======================================
  Hits        21744    21744           
  Misses        631      631           
  Partials        6        6           

Flag	Coverage Δ
explorer-puller	99.90% <ø> (ø)

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Files with missing lines	Coverage Δ
explorer/puller/puller/db/SymbolDatabase.py	100.00% <ø> (ø)

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[Jaguar0625]

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