1.47.54

• Fixed high CPU usage caused by repeated Tcl thread alerts while connections waited for socket I/O.
• Added readiness-based handling for HTTP/TLS reads, handshakes, writes, and keepalive connections.
• Improved timeout, connection teardown, fragmented-header, buffered-TLS, and partial-write handling.
• Added Tcl and Python readiness regression tests.
• Renewed the client-authentication test certificates and improved TLS tests.
• Updated CMake to build against Tcl stubs, removing the direct Tcl shared-library dependency.
• Verified builds and full test suites with Tcl 8.6 and Tcl 9.1.