fix: widen knowledge processing span names

[godququ5-code]

Description

Wiki summary pages generate span names such as postprocess.wiki.page[summary/<knowledge-id>], which are 67 characters long. The knowledge_processing_spans.name column and its GORM model were limited to 64 characters, causing PostgreSQL inserts to fail and leaving Wiki-enabled documents stuck in finalizing.

This change:

• adds migration 000066 to widen knowledge_processing_spans.name to VARCHAR(256)
• keeps the down migration safe by truncating names back to 64 characters before narrowing the column
• aligns the GORM model and SQLite test schemas with the production column width
• adds a regression test covering the actual Wiki summary span name shape

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 💥 Breaking change
• 📚 Documentation update
• 🎨 Refactor
• ⚡ Performance improvement
• 🧪 Test
• 🔧 Configuration / Build / CI

Related Issue

Fixes #1941

Testing

• go test ./internal/types ./internal/application/repository ./internal/application/service -count=1
• golangci-lint run --new-from-rev=HEAD (0 issues)
• PostgreSQL 16 migration check:
  • the existing VARCHAR(64) schema rejects the 67-character Wiki summary span name
  • migration up allows the insert and preserves all 67 characters
  • migration down restores a 64-character column and truncates the value to 64 characters

Full make test was also attempted. Unrelated environment-dependent tests fail because the local DocReader service is not running on localhost:50051, and existing Notion/remote-image tests are blocked by the current SSRF rules for 127.0.0.1. The packages changed by this PR pass.

Full make lint reports existing repository-wide findings; diff-scoped lint reports no new issues.

Checklist

• make fmt && make lint && make test pass locally
• Self-reviewed the code
• Added/updated tests covering the change
• Updated related documentation (README, docs/, Swagger annotations, etc.)
• Breaking changes are clearly called out in the description above

Screenshots / Recordings

Not applicable; this is a database schema fix.

[godququ5-code]

Thanks for addressing this upstream. PR #2020 has now merged the same schema expansion and also adds deterministic hash-suffix truncation for names beyond the new column limit, so this PR is superseded. Closing to avoid duplicating the merged fix.