FormulaInfo復元時に保存bytecodeを信頼しない

[opaopa6969]

Summary

• require source formula when restoring FormulaInfo
• always rebuild calculators from formula text under the current execution policies
• ignore persisted Java/class bytecode as an execution input
• document the trust boundary and programmatic precompiled-artifact distinction
• add regression coverage for tampered bytecode and bytecode-only documents

A stored MD5 cannot authenticate bytecode because the digest and payload are editable in the same document. Rebuilding also preserves JavaCodeBlockPolicy as the authority for formulas containing embedded Java.

Tests

• ./mvnw -Dtest=FormulaInfoStoredByteCodePolicyTest,FormulaInfoParserTest,FormulaInfoListTest,FormulaInfoExecutionBackendSelectionTest,JavaCodeBlockPolicyTest test
  • 17 tests, 0 failures
• ./mvnw test
  • 684 tests, 0 failures, 0 errors, 9 skipped
  • 8m28s locally

Closes#83