v1.12.2

<!-- Release notes generated using configuration in .github/release.yml at v1.12.2 -->

## What's Changed
### ✨ New Features
* feat(components): upgrade Guardrails with optional combined rule and model checks by @mansura-habiba in https://github.com/langflow-ai/langflow/pull/14934
### 🐛 Bug Fixes
* fix: preserve restricted-component diagnostics in streamed errors by @erichare in https://github.com/langflow-ai/langflow/pull/14999
* fix: stop double-prefixing catalog policy CHECK names under naming conventions by @breken-ai in https://github.com/langflow-ai/langflow/pull/15007
* fix(migrations): stop double-prefixing CHECK constraint names under the naming convention by @erichare in https://github.com/langflow-ai/langflow/pull/15009
* fix(db): give the flow_version CHECK constraint one name across create paths by @erichare in https://github.com/langflow-ai/langflow/pull/15010
* fix(deps): remove DiskCache and patch ML vulnerabilities by @erichare in https://github.com/langflow-ai/langflow/pull/15019
* fix: allow vectorizing multiple knowledge base columns by @erichare in https://github.com/langflow-ai/langflow/pull/15016
* fix(ci): start patch-release RCs at rc0 when the SDK is unchanged by @erichare in https://github.com/langflow-ai/langflow/pull/15022
* fix(assistant): restore Ollama support in the Langflow Assistant by @Cristhianzl in https://github.com/langflow-ai/langflow/pull/15005
* fix(tasks): stop awaiting Celery's synchronous revoke result by @erichare in https://github.com/langflow-ai/langflow/pull/15026
* fix(frontend): keep auto-login auth when the session probe answers late by @erichare in https://github.com/langflow-ai/langflow/pull/15028
* fix(graph): keep Component.stop() branches inactive while a sibling completes by @erichare in https://github.com/langflow-ai/langflow/pull/15029
* fix(knowledge): honour Vectorize/Identifier flags typed into the column table by @erichare in https://github.com/langflow-ai/langflow/pull/15030
* fix(lfx): percent-encode "/" in database connection passwords by @viktoravelino in https://github.com/langflow-ai/langflow/pull/15032
* fix(components): read Guardrails AI-check replies via BaseMessage.text by @erichare in https://github.com/langflow-ai/langflow/pull/15042
* fix(api): stop 500 responses from echoing response-validation input by @erichare in https://github.com/langflow-ai/langflow/pull/15041
* fix(responses): stream failed agent tool calls as function_call items by @erichare in https://github.com/langflow-ai/langflow/pull/15031
* fix(api): report missing flows and versions during concurrent deletes by @erichare in https://github.com/langflow-ai/langflow/pull/15065
* fix(assistant): validate component params before applying any of them by @viktoravelino in https://github.com/langflow-ai/langflow/pull/15036
* fix(lfx): accept double-encoded Google service account keys by @viktoravelino in https://github.com/langflow-ai/langflow/pull/15064
* fix(components): inject loop item into every fan-out branch by @gingeekrishna in https://github.com/langflow-ai/langflow/pull/14965
* fix(deps): override shell-quote and websocket-driver in docs/ to patched versions by @boazgarty in https://github.com/langflow-ai/langflow/pull/15015
* fix(api): bound message-history reads to stop editor freeze on flows with large chat history by @AhsanAkhlaq in https://github.com/langflow-ai/langflow/pull/15051
* fix(assistant): preserve dependent choices and token limit resets by @Simonzhaohui in https://github.com/langflow-ai/langflow/pull/15001
* fix: db session commit before response by @Jkavia in https://github.com/langflow-ai/langflow/pull/15078
* fix(api): index message history and handle nullable text by @Cristhianzl in https://github.com/langflow-ai/langflow/pull/15076
* fix(responses): stream the final message when no tokens were streamed by @erichare in https://github.com/langflow-ai/langflow/pull/15080
* fix: allow concurrent flow version attachments on PostgreSQL by @erichare in https://github.com/langflow-ai/langflow/pull/15086
* fix: warn when restricted workflows substitute saved component code by @erichare in https://github.com/langflow-ai/langflow/pull/15090
* fix(lfx): close temp file before deleting failed cloud downloads by @viktoravelino in https://github.com/langflow-ai/langflow/pull/15074
* fix(jobs): atomically claim expired HITL pauses by @olayinkaadelakun in https://github.com/langflow-ai/langflow/pull/15096
### 📝 Documentation Updates
* docs: updates to guardrails component and legacy by @mendonk in https://github.com/langflow-ai/langflow/pull/15073
### 🛠 Maintenance Tasks
* refactor(deps): migrate initial LangChain Community integrations by @erichare in https://github.com/langflow-ai/langflow/pull/15020
* chore: 1.12.2 dep upgrade by @Adam-Aghili in https://github.com/langflow-ai/langflow/pull/15075

## New Contributors
* @breken-ai made their first contribution in https://github.com/langflow-ai/langflow/pull/15007
* @boazgarty made their first contribution in https://github.com/langflow-ai/langflow/pull/15015
* @AhsanAkhlaq made their first contribution in https://github.com/langflow-ai/langflow/pull/15051

**Full Changelog**: https://github.com/langflow-ai/langflow/compare/v1.12.1...v1.12.2