ent-v2.2.3-base

## What's Changed
* cherrypicked key id selection to fallbacks by @akshaydeo in https://github.com/maximhq/bifrost/pull/7470
* fix: move routing key pins with their routes when session affinity reorders the chain so a pinned key is never looked up under the wrong provider by @Pratham-Mishra04 in https://github.com/maximhq/bifrost/pull/7468
* fix: carry route-level key pins through session affinity reorder and add e2e session-affinity matrix tests by @Pratham-Mishra04 in https://github.com/maximhq/bifrost/pull/7469
* fix: drop session bindings the request followed into a failure and match route by provider and model together by @Pratham-Mishra04 in https://github.com/maximhq/bifrost/pull/7473
* test: add session affinity matrix cases 12–13 (binding names provider+model, binding forgotten after key-selection failure) and new harness routing rules (`anthropic-first`, `anthropic-first-other-model`, `vertex-badkey`) by @Pratham-Mishra04 in https://github.com/maximhq/bifrost/pull/7474
* fix: update UI path to correctly handle user labels toggle by @roroghost17 in https://github.com/maximhq/bifrost/pull/7490
* fix(databricks): merge multi-part system prompts for Gemini-backed endpoints by @impoiler in https://github.com/maximhq/bifrost/pull/7461
* fix: openai reasoning and params fixes by @TejasGhatte in https://github.com/maximhq/bifrost/pull/7239
* fix: openai prompt cache breakpoint by @TejasGhatte in https://github.com/maximhq/bifrost/pull/7240
* fix: responses type fixes by @TejasGhatte in https://github.com/maximhq/bifrost/pull/7241
* feat: async tool execution in responsses by @TejasGhatte in https://github.com/maximhq/bifrost/pull/7242
* fix: gpt-6 sol and luna support none effort by @TejasGhatte in https://github.com/maximhq/bifrost/pull/7492
* tests: harness tests gpt-6 by @TejasGhatte in https://github.com/maximhq/bifrost/pull/7496
* fix: openrouter cache breakpoint and harness fix by @TejasGhatte in https://github.com/maximhq/bifrost/pull/7521
* 2.2.3 changelog by @akshaydeo in https://github.com/maximhq/bifrost/pull/7528
* bedrock encrypted content decodding fix by @akshaydeo in https://github.com/maximhq/bifrost/pull/7529
* kimi + codex fix. fixes mcp tool name length by @akshaydeo in https://github.com/maximhq/bifrost/pull/7530
* tool_search support for gpt-6 models for non-openai providers by @akshaydeo in https://github.com/maximhq/bifrost/pull/7534


**Full Changelog**: https://github.com/maximhq/bifrost/compare/ent-v2.2.2-base...ent-v2.2.3-base