v0.15.0

What's Changed

• Add detached-trace invocation span (0061) by @chris-colinsky in #168
• Strip spec references and process labels from docstrings by @chris-colinsky in #169
• Add per-attempt LLM spans under call-level retry (0050) by @chris-colinsky in #170
• Add Langfuse trace.userId / trace.sessionId population (0064) by @chris-colinsky in #171
• Add per-fetch prompt cache control cache_ttl_seconds (0072) by @chris-colinsky in #172
• Pin spec v0.64.0 for proposal 0073 (textual-only) by @chris-colinsky in #173
• Add failure-isolation catch gate and cause-chain classification primitive (0074) by @chris-colinsky in #174
• Add callable and conditional parallel branches (0075) by @chris-colinsky in #175
• Add tool-call request observability on LLM spans (0076) by @chris-colinsky in #176
• Add opt-in OTel GenAI metrics (0067) by @chris-colinsky in #177
• Add tool-execution observability (0063) by @chris-colinsky in #178
• Add detached fan-out-instance error span test by @chris-colinsky in #179
• Guard against unaccounted observability conformance fixtures by @chris-colinsky in #180
• Pin spec v0.70.1: wire fixture 110, defer rerank by @chris-colinsky in #181
• chore(release): v0.15.0-rc1 by @chris-colinsky in #182
• chore(release): v0.15.0 by @chris-colinsky in #183

Full Changelog: v0.14.0...v0.15.0