docs(buglog): log follow-ups of the P0 fixes (bug-1958..bug-1966)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.wolf/bugs/bug-1963.md

@@ -0,0 +1,49 @@
+---
+id: "bug-1963"
+status: "investigating"
+status_updated: "2026-10-10"
+status_note: "suspected; confirm with a scheduler fixture test"
+component: "scheduler"
+severity: "wrong-result"
+timestamp: "2026-10-10T10:16:09Z"
+last_seen: "2026-10-10T10:16:09Z"
+occurrences: 1
+files: ["src/scheduler/src/host_iter.c"]
+tags: ["scheduler", "host"]
+related: []
+---
+
+# bug-1963: xce_scheduler host iteration offers unavailable or reconciling hosts as placement candidates
+
+## Description
+**Observed:** (source reading; follow-up of the 2026-10-10 P0 fixes (bug-1936..1957))
+Suspected (reported by the bug-1939 fix, not verified): `sched_host_iter_next()` (`src/scheduler/src/host_iter.c`) skips admin-closed hosts since bug-1939 but not `XCE_WORKER_UNAVAIL` or `XCE_WORKER_RECONCILING`; other checks (`resource.c:704,887`, `core_session.c:136`) are accounting skips, not placement filters.
+
+**Expected:** Unavailable and reconciling hosts get no new placements.
+**Impact:** Possible dispatch to a dead or reconciling host (dispatch then fails and is retried).
+**Found by:** follow-up of the 2026-10-10 P0 fixes (bug-1936..1957)
+## Environment
+- OS: no /etc/os-release; Docker container; NixOS kernel; kernel Linux 6.18.33 x86_64
+- libc: glibc 2.42-47 (interpreter /nix/store/wb6rhpznjfczwlwx23zmdrrw74bayxw4-glibc-2.42-47/lib/ld-linux-x86-64.so.2)
+- Toolchain: gcc (GCC) 15.2.0, meson 1.9.1
+- Build: asan (xce.build)
+- Code: scheduler-framework @ 19be145d-dirty
+- Deployment: any (found by source reading; confirmed by the RED test of the fix)
+
+## Reproduction
+1. Mark a host UNAVAIL in a scheduler fixture and check whether the iterator offers it.
+- Frequency: deterministic (by code reading; confirmed by the RED test of the fix)
+- Evidence: the code sites quoted in Description; no logs kept.
+## Root cause
+TODO: required for fixed/partial
+
+## Fix
+TODO: required for fixed/partial
+
+## Verification
+- Test: TODO: name + file; RED before the fix, GREEN after
+- Suites: TODO: suite results and build profile
+- Live: TODO: soak/deploy run, or n/a and why
+
+## References
+- Related: none