fix: buffer split generic invoke tags

[EvanProgramming]

Summary

• retain partial generic invoke/control tags through arbitrary SSE chunk boundaries
• consume attributes, call bodies, and closing tags before Web content events
• add every-boundary filter coverage plus persisted SSE regression

Validation

• python -m unittest tests.test_streaming -v (6 passed)
• make lint
• KYROZEN_DB_PATH= make docs-check
• git diff --check
• full local suite reached 193 tests; loopback socket tests and isolated wheel build are sandbox/offline blocked; CI is required

Fixes #146