elelem v0.1.1 — documentation accuracy

No API or behaviour change; every Go edit is a comment.

Reattached two exported doc comments (Client.Driver, DefaultTokenCounter) that
a stray // plus a blank line had detached, leaving them absent from pkg.go.dev.

Corrected documentation that did not match the code: tool denial is a
ToolCallDecision carrying a required CallID, not an error from OnToolCallStart
or Tool.PreRun (both of which abort the run, and a CallID-less decision fails
open); history limiting is also disabled when the output reserve is >=
ContextSize; the custom limiting-handler example could orphan a tool result;
ProviderError must be returned as a pointer; the token-counter resolution order
includes the client tier; response repair needs no strict validation and skips
refusals; tool-result size is bounded only when WithMaxToolResultTokens is set;
INFO covers two events, not lifecycle.

README reorganised around an above-the-fold example, a per-area table, a
drivers section and a logging section.