E142 - Claude Code 2.1.284 and the Sonnet 5.5 Shift

We unpack Claude Code 2.1.284 and the quiet switch to Sonnet 5.5, from the 1M-token context window and cheaper cache reads to the new 512-token cache minimum. Plus: adaptive thinking defaults, tool-calling changes, keybinding controls, and the token-counting gotchas that could affect your bill.