Release v3.12.6

What's Changed

• Send the network error code when host settings can't load by @ignaciojimenezr in #5733
• Lift each compare card's summary only when its numbers change by @SebasKoria in #5714
• Stop false update failures from expired background records by @ignaciojimenezr in #5743
• Don't crash when stopping a test-editor run by @ignaciojimenezr in #5745
• Stop a deleted run from crashing the run detail page by @nachocossio in #5725
• Run the NUX first-run E2E in CI again by @nachocossio in #5723
• Stop the trace viewer setting state on every streamed token by @SebasKoria in #5750
• Stop the agent resending forever after its last step by @ignaciojimenezr in #5734
• Changelog: agent step limit fix (2026-09-30) by @mintlify[bot] in #5751
• SDK: reasoning-effort capability and identity helpers (effort plan, PR 1) by @chelojimenez in #5749
• Harden telemetry relay limits (MJ-015) by @olartgabo in #5740
• Harden v1 read proxy errors (MJ-020) by @olartgabo in #5741
• Harden response headers (MJ-016) by @olartgabo in #5742
• Harden agent tool access (MJ-008) by @olartgabo in #5744
• Harden v1 read errors (MJ-021) by @olartgabo in #5747
• Send feedback from the app: Support form and error-card report link by @chelojimenez in #5715
• Effort: capability on model rows and identity by config key (effort plan, PR 3) by @chelojimenez in #5754
• Keep a closed trace row closed while a reply streams by @ignaciojimenezr in #5752
• Fix swarm retries for busy spending reservations by @ignaciojimenezr in #5756
• Harness: refuse a reasoning effort the adapter has not verified (effort plan, PR 4) by @chelojimenez in #5757
• Spine: each prompt's tools under that prompt, suite evaluators folded by @chelojimenez in #5759
• ci: Trivy-scan the three Railway container images by @olartgabo in #5763
• chore: release changeset for inspector, CLI, and SDK by @ignaciojimenezr in #5773
• chore(release): version packages (3.12.6) by @chelojimenez in #5774

Full Changelog: v3.12.5...v3.12.6