mods/agents-md: a Read attaches no nested AGENTS.md where the engine attaches nothing to a turn - #95417

mods/agents-md's tool.call hook on Read now attaches no nested AGENTS.md in a run where the engine itself attaches nothing to a turn: --bare (which sets CLAUDE_CODE_SIMPLE) or CLAUDE_CODE_DISABLE_ATTACHMENTS, each read on every Read through $.env.get with the spellings the engine reads its own switches with (1, true, yes, on), so a settings env block that flips one mid-session is followed. The prompt.context walk is unchanged: where the engine loads no instruction files it finds none. README, hooks.json and the module's JSDoc say so. Checked: tsc -p mods/tsconfig.json, claude plugin validate mods/agents-md, and claude plugin test on every mod under 2.1.276 and 2.1.277.