record milestone 15 outcomes in spec and tech debt report

TECH_DEBT.md

@@ -16,6 +16,17 @@ Dominant themes, in order of threat:
 
 ## Theme 1: The verification pipeline is compromised (11 findings)
 
+> **Status: all 11 findings closed by milestone 15 (commit 9f8a5cd,
+> 2026-08-07).** Two corrections to the findings themselves, discovered
+> during implementation: the teardown-abort diagnosis was wrong — no binary
+> aborts under `zig build`; the `failed command` label is a zig 0.16.0
+> build-runner display artifact (root cause recorded in
+> specs/milestone-15.md ruling 3) — and the http_util "decoded segment
+> never gains a `/`" invariant was false (`%2F` decodes to a literal `/`);
+> the count-based invariant that replaced it is recorded in ruling 6c.
+> The aarch64-under-qemu acceptance line is environment-blocked on this
+> host (no `qemu-aarch64`); the aarch64 suite cross-compiles clean.
+
 The repo's history proves this theme's stakes: commit 35f2324 fixed a process-killing bug that 1284 green hermetic tests hid. Several of the guards that should prevent a recurrence are absent or inert.
 
 - **[medium] .gitea/workflows/ci.yml:5 — CI triggers only on `main` while work happens on `master`.**