v0.1.2

Fix: network transport failures now surface properly.

• Network-level transport failures now throw LlmError with code TRANSPORT instead of leaking undici's bare TypeError: fetch failed (whose raw detail, e.g. UNKNOWN, previously surfaced as the whole error).
• Both the generate request and a mid-stream read are wrapped, with the original error chained as cause so errorChain renders the full diagnosis.
• Caller aborts propagate unchanged (not relabeled).
• Lets dsh's retry policy recognize and retry transient network failures.