feat(#18): affect.fetch — adopt bifrost 0.10.0 mandatory fetch (D1 prerequisite)

bifrost 0.10.0's _supports_affect_plane (bifrost/affect.py:75-80) now requires a
callable fetch for the affect capability to advertise/dispatch at all (INV-012
strong-or-absent), so an emit-only store 400s on EVERY affect op — repinning past
the affect.fetch release (#12/#13) breaks our shipped affect plane until fetch
exists. Implement affect.fetch as a thin async wrapper over the existing get()
read seam, conformed verbatim to the reference InMemoryAffectStore.fetch:
{"found": False} or {"found": True, "snapshot": <verbatim>}, AffectInvalidArguments
on empty ids, opaque (INV-001 — never reads pad/valence).

This is the forced prerequisite for the #18 D1 composite (build_combined_app),
and a new Worldtree I/O point consumed (affect read-back over bifrost).

- Repin bifrost>=0.8.0 -> >=0.10.0 (uv lock: 0.8.0 -> 0.10.0)
- affect_store.py: add async fetch() over get()
- contract bifrost_affect_provider v1.2: fetch FN block + INV-010 (cap = supported+emit+fetch)
- tests: 3 fetch unit + parity_vs_reference_fetch through dispatch_affect_call
- suite 482 -> 486 green

uv.lock

@@ -190,14 +190,14 @@ wheels = [
 
 [[package]]
 name = "bifrost"
-version = "0.8.0"
+version = "0.10.0"
 source = { registry = "https://gitea.phasefinal.com/api/packages/vh/pypi/simple/" }
 dependencies = [
     { name = "jsonschema" },
 ]
-sdist = { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.8.0/bifrost-0.8.0.tar.gz", hash = "sha256:28194877c81a056a0803b052e86902c092e965d4ce63a5623d7a31240cedb645" }
+sdist = { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.10.0/bifrost-0.10.0.tar.gz", hash = "sha256:aba1869dba68d921f2e0be8fb560277073da09ec2ad5f410e226cacd5e84fe1a" }
 wheels = [
-    { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.8.0/bifrost-0.8.0-py3-none-any.whl", hash = "sha256:2aac5e4a7828d718389748a78dae6baeb5e9ee4a801a10c427c06c5cc7ed6597" },
+    { url = "https://gitea.phasefinal.com/api/packages/vh/pypi/files/bifrost/0.10.0/bifrost-0.10.0-py3-none-any.whl", hash = "sha256:88adbce23fa8840a14f9493e4f0cf6f9320f4950845f7a6080387defe574a5cc" },
 ]
 
 [[package]]
@@ -1052,7 +1052,7 @@ wheels = [
 
 [[package]]
 name = "ratatoskr"
-version = "0.17.14"
+version = "0.17.15"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },
@@ -1086,7 +1086,7 @@ web = [
 
 [package.metadata]
 requires-dist = [
-    { name = "bifrost", marker = "extra == 'provider'", specifier = ">=0.8.0", index = "https://gitea.phasefinal.com/api/packages/vh/pypi/simple/" },
+    { name = "bifrost", marker = "extra == 'provider'", specifier = ">=0.10.0", index = "https://gitea.phasefinal.com/api/packages/vh/pypi/simple/" },
     { name = "httpx", specifier = ">=0.27" },
     { name = "httpx-sse", specifier = ">=0.4" },
     { name = "jsonschema", marker = "extra == 'provider'", specifier = ">=4" },