Update Realm to main as of 2026-07-01

[elliottslaughter]

Passes CPU and GPU tests locally on Sapling.

Changes:

$ g l 42f7484a8..dba83452d
* dba83452d4 (HEAD -> main, origin/main, origin/HEAD) [DOCS] Add missing workflow for documentation update for published releases
* 76631cdb73 (tag: v26.7.1) Fix DMA Forward Progress (#451)
* 6ba5bd286b Support for GDB Backtraces of All Threads (#435)
* c6aca815b6 Alternative Network Quiescence Algorithm (#428)
* 4c5e91c3aa Fix Active Message Payload Fragmentation (#410)
* 74e7286bd7 Link GEX wrapper target against GASNet (#449)
* ecbbfe9168 Make advanced/transpose CUDA reduction kernels optional in register_reduction (#445)
* da39e1af7b ucx: Skip unsupported config knobs in ucp_config_modify (#432)
* f0f8ea08ac Fix the owner of completion queue by using compqueue_owner_node() (#441)
* 3fe7c85896 GASNetEX: fix pktbuf_close race that can free an actively-used buffer (#444)
* eedd0c47cd Fix Latent Get Address Bug (#437)
* 826f74ca8d Fix Instance ID Reuse (#442)
* 93fd5f9881 Background Copy Planning (#406)
* e56eef0c85 Fix Address List Crash (#436)
* 6c51034c3b Rewrite the cuhook using cupti (#332)
* 782f7a56b8 Auto-discover the MPI bootstrap for UCX, and force if explicitly requested (#434)
* e4c1b9c7b8 Upgrade builtin UCX to 1.20.1 and UCC to 1.7.0 (#431)
* d7ace4350b Fix Transfer Descriptor Lifetime (#433)
* d66889e608 Fix GASNetEX Polling Bug (#430)
* 4515720df3 Fix Use-After-Free Race in Push Packets (#429)
* 49056b6499 realm: Remove file descriptor fallback if fabric handles don't work (#427)
* 01cf229395 Fix Scatter Test Race (#422)
* 2c00e9fbd4 Fix Background Work State Machine (#426)
* 028915c6bd More Fast Reservation Fixes (#425)
* d9c0cb75e5 Fix Fast Reservations Again (#423)
* c271dec00a Copy Planning Timeout (#419)
* d393ba4e3a Fix Event Triggering Race (#420)
* 30da2be37b Fix GASNet Races (#409)
* 442cab573a Support transfers for layouts with multiple id-indexed fields (#284)
* f3373796cc Sm/cuda redop opt (#330)
* 87ec0ada55 Spin Lock Fixed 3 (#415)
* 1b9041582d Fix Spin Locks 2 (#414)
* c178f8242e Fix Reduction Tutorial Race (#411)
* c28d3f9932 Fix Spin Lock Hang (#407)
* ea52777415 Fix Missed Wakeup in Remote Processor Group Spawns (#408)
* fa0f8685b7 Fix the redop path when p2p is disable (#402)
* 77e872a5a9 cmake: make realm_kokkos a PUBLIC dependency of realm (#400)

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This change is