fix(ingest): read Spring AI's Anthropic and Bedrock Converse usage as cache-exclusive - #1176

🟢 Confidence 4/5 · likely safe to merge
One match arm on gen_ai.system, guarded, with the three prod sessions and the inclusive OpenAI case tested; the Spring AI enum strings themselves are the author's reading of its source.
_{quality 100/100 · no findings · tests covered · risk medium}

Adds a spring_ai arm to the ingest cache-exclusivity rule, read per span from gen_ai.system, so Spring AI's Anthropic and Bedrock Converse usage stops losing the cache from the prompt. Contained and correct; safe to merge.

• input_excludes_cache takes the Span and branches on gen_ai.system for spring_ai
• Spring AI anthropic/bedrock_converse spans read cache-exclusive; openai stays inclusive
• New test spring_ai_anthropic_and_converse_are_cache_exclusive covers the three prod sessions

_{163c28a · Updated on every push. Reply "won't fix" to dismiss a finding, or mention @maple-review-bot to ask about one.}