kyte-php v4.6.1

Bug Fix (regression from 4.6.0): large MCP tool responses corrupt the session → read_page (and other large reads) fail

A read_page against a large page (≈300KB+ of HTML) failed with a 400 and "Control character error, possibly incorrectly encoded". Root cause is the new DbSessionStore from 4.6.0: it defined KyteMCPSession.payload as TEXT (64KB max).

The streamable-HTTP SDK persists its outgoing-message queue (_mcp.outgoing_queue) — the full JSON-RPC tool response — inside the session payload between handling and delivery. A large read produces a ~800KB response (the SDK also duplicates content as a text block and structuredContent); that overflows the 64KB column, MySQL silently truncates it at 65535 bytes, and the truncated JSON then fails json_decode on the next read → the ctrl-char error, surfaced to the client as a 400.

The FileSessionStore that 4.6.0 replaced wrote to files with no size cap, so large reads worked there — this is a parity regression, not a pre-existing bug.

Fix: KyteMCPSession.payload is now LONGTEXT (model type lt). migrations/4.6.1_mcp_session_payload_longtext.sql runs ALTER TABLE ... MODIFY payload LONGTEXT and purges any sessions already truncated under the old column (LENGTH(payload) >= 65535) so stale corrupt rows don't keep failing on resume. Single-instance installs on the file backend are unaffected. Run the migration on every install that took 4.6.0 with the default DB store.