fix(bedrock): preserve complete calls

[calclavia]

The published Bedrock adapter drops complete tool calls when the same response ends with max_tokens, even though it emits identical arguments for tool_use. Parse stopped tool blocks at the length terminal with the existing secure parser, preserve complete calls, and retain the original finish reason and usage.

Incomplete, empty, and unsafe argument buffers remain parameter deltas at the length terminal. Normal completion keeps its existing parse-error behavior. This change adds no execution or transport retry policy.

This PR targets feat/ai-bedrock, the source branch whose commit 08590cdf2c matches the published @tardie/ai-bedrock@0.0.1 source. The package is absent from clavia/ai-providers.

Validation: the portable public-layer reproduction fails against the published package and passes with the generated installation patch; all 19 Bedrock provider tests, package TypeScript check, formatting, and repository pnpm check pass. The regression includes complete, partial, unsafe, and empty buffers in one length-completed stream and verifies usage.