chore(main): release 0.18.0

[github-actions]

🤖 I have created a release beep boop

0.18.0 (2026-08-17)

⚠ BREAKING CHANGES

• python: batched kernel dispatch — one submission, one fence (#1889)
• engine: GLSL is the kernel source contract — vendored compiler, keyed cache (#1885)
• engine: CpuReadbackBridge, set_cpu_readback_bridge and its FullAccess mirror are deleted; open_cpu_readback_staging is added to the escalate wire.
• plan: run_cpu_readback_copy(buffer_to_image) now refuses a staging that has never been filled from its surface.
• engine: run_compute_kernel and register_compute_kernel change shape.
• engine: Texture::native_handle() returns a DMA-BUF fd whose ownership transfers to the caller; previously the texture closed it at drop. No in-tree caller exists.
• engine: a pool surface id names the frame — recycled ids fail loudly, never serve another frame's pixels (#1877)
• engine: subscribe() returns Result and registers its subscriber before returning, so no event is lost to the establishment window (#1875)
• python: delete the wheel duplicate media_clock_now_ns export (#1860)
• engine: audio tick timestamps carry the machine epoch (#1859)
• engine: MediaClock carries the machine monotonic epoch (#1858)
• retire the manifest, schema and codegen layer from the consumer trees (#1854)
• sdk: delete the @org/package/Type identity grammar and streamlib-idents (#1851)
• engine: the registry, graph and control plane key on the import path (#1850)
• idents: delete the orphaned package layer — resolver, manifest, lockfile, package source, archive (#1843)
• sdk: strip the type from port declarations and control-plane rendering (#1831)
• engine: streamlib::schemas::current_schema_idents and current_schema_definition are removed, along with the GET /api/schemas and GET /api/schemas/{name} control-plane endpoints.

Features

• ci: check-clock-usage — enforce the wall-clock allowlist (#1861) (1494b08), closes #1728
• engine: CPU readback becomes an always-present GpuContext capability (#1883) (d99755b)
• engine: delete the embedded schema registry (#1827) (fc6be3f)
• engine: GLSL is the kernel source contract — vendored compiler, keyed cache (#1885) (83d81d4)
• engine: named N-binding compute dispatch from Python, end to end (#1882) (106570d)
• engine: surface checkout leases — a held frame's pool slot is never rehanded (#1869) (7e90288)
• engine: the display name disambiguates duplicates within one graph (#1845) (c9e5fa0)
• python: batched kernel dispatch — one submission, one fence (#1889) (19eafe6)
• python: the typed cast claims its frame — read(into=VideoFrame) pins the surface, drop releases it (#1871) (ed098d4)
• sdk: every processor descriptor carries its class's import path (#1848) (afae87c)
• sdk: strip the type from port declarations and control-plane rendering (#1831) (45cff3a), closes #1816

Bug Fixes

• engine: a pool surface id names the frame — recycled ids fail loudly, never serve another frame's pixels (#1877) (5a7b8dd)
• engine: a surface-share export has exactly one fd owner — the texture DMA-BUF export mints per call instead of memoizing (#1881) (78c5bc8)
• engine: audio tick timestamps carry the machine epoch (#1859) (a3cc658)
• engine: bound every wire-derived length the frame-header read path trusts (#1832) (cbd6b9e)
• engine: cross-process device export reads the pooled backing, never the producer's ring (#1868) (53d5410)
• engine: MediaClock carries the machine monotonic epoch (#1858) (614bfa7), closes #1725
• engine: per-link iceoryx2 port reclaim for helper-process endpoints on disconnect (#1862) (e76762e)
• engine: RHI test fixtures build the video profiles and export memory production builds (#1895) (db09366)
• engine: subscribe() returns Result and registers its subscriber before returning, so no event is lost to the establishment window (#1875) (655e74d)
• engine: the tone mapper leaves each image in a layout its usage allows (#1894) (110876b)
• rhi: the extension-properties buffer outlives the names it lends (#1847) (11f5671), closes #1846

Performance

• engine: the staging cache stops allocating on every lookup (d99755b)
• xtask: optimize the lint gates so the test suite stops paying for them (#1849) (1385bd4)

Code Refactoring

• engine: the registry, graph and control plane key on the import path (#1850) (4e2ac4b)
• python: delete the wheel duplicate media_clock_now_ns export (#1860) (fd44620)
• sdk: delete the @org/package/Type identity grammar and streamlib-idents (#1851) (d0dcea3)

Documentation

• plan: re-cut the REMOVED bullet this change would have falsely retired (d99755b)

Miscellaneous

• idents: delete the orphaned package layer — resolver, manifest, lockfile, package source, archive (#1843) (96717c8)
• retire the manifest, schema and codegen layer from the consumer trees (#1854) (d69e753)

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