v0.4.3

Restore scientific source material and improve questionnaire-presence metadata while preserving numerical estimates.

• Restore 120 original fields across eight polls, including literal written responses, with source and dictionary checks.
• Preserve original Michigan and Northern Ireland data files and Michigan, Europolis, and Climate reference materials in their poll folders. All 68 Word documents have registered PDF companions.
• Add 21 verified Climate attitude items and distinguish observed questionnaires from missing forms consistently, including Tanzania, Denmark, and Vermont.
• Correct five invalid New Haven item codes and preserve documented don't-know responses. Remove redundant occupation sidecars after exact comparison with the canonical source.

All 1,027,858 existing numerical respondent measures and 63,234 survey weights remain unchanged. The release rebuilds all 57 output files byte-for-byte from a clean source archive without Git history or vault files. Local checks, independent review, and GitHub validation passed. Remaining source and coding questions are recorded in docs/poll-issues.md.