New src/thought/ module containing tools and infrastructure shared
between poc-agent and subconscious agents: memory operations, file
tools, bash, context window management.
Currently coexists with agent/tools/ — next step is to wire up both
agent/ and subconscious/ to use thought::dispatch instead of
duplicating the routing logic.
Move dbglog macro to lib.rs so it's available crate-wide regardless
of module compilation order.
