Fix system tool parser dropping text and blocking follow-up tool calls

[siewcapital]

Summary

• keep parsing after a completed system tool call instead of halting the stream
• preserve assistant text emitted after a tool codeblock
• allow a second (or later) tool codeblock in the same assistant response stream
• update tool-instruction suffix to remove the single-tool/terminal-only restriction
• extend parser tests to cover post-tool text preservation and multi-tool streaming

Why

Issue #11074 highlights that the current interceptor enforces a positional assumption (single terminal tool call). That causes a capability gap for system-message tool parsing compared with native tool calling behavior.

Testing

• Added/updated vitest cases in:
  • core/tools/systemMessageTools/toolCodeblocks/interceptSystemToolCalls.vitest.ts
• Could not execute vitest in this environment because project dev dependencies are not installed (vitest: command not found).

Closes #11074

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Summary by cubic

Fixes the system tool parser so it preserves assistant text and supports multiple tool codeblocks in a single response instead of stopping after the first call. Closes #11074 and aligns system-message tool parsing with native tool calling.

• Bug Fixes
  • Keep parsing after a completed tool call; no premature halt.
  • Preserve assistant text after tool codeblocks (including newline).
  • Support multiple tool codeblocks in one assistant message.
  • Update system message suffix to allow multi-tool calls; add tests for post-tool text and multi-tool streams.

^{Written for commit 653adb1. Summary will update on new commits.}

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[cubic-dev-ai]

No issues found across 3 files

[Co-Messi]

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