Make the `tipc` CI leg blocking

The refreshed PR matrix passes on Ubuntu with the TIPC kernel
module loaded, along with the TCP, UDS and macOS legs. Remove the
temporary `continue-on-error` expression so future TIPC
regressions block CI.

Prompt-IO: ai/prompt-io/opencode/20260819T003326Z_53516b09_prompt_io.md

(this patch was generated in some part by `opencode` using
`gpt-5.6-sol` (`openai`))

.github/workflows/ci.yml

@@ -92,12 +92,6 @@ jobs:
     timeout-minutes: 16
     runs-on: ${{ matrix.os }}
 
-    # XXX the `tipc` leg stays NON-blocking until the `modprobe`
-    # step below is proven stable on GH's runners; flip this off
-    # once it's had a few green runs. See plan 01 §7.3 in
-    # `ai/tpt-backends/01_tipc_backend.md`.
-    continue-on-error: ${{ matrix.tpt_proto == 'tipc' }}
-
     strategy:
       fail-fast: false
       matrix:

ai/prompt-io/opencode/20260819T003326Z_53516b09_prompt_io.md

@@ -0,0 +1,29 @@
+---
+model: openai/gpt-5.6-sol
+service: opencode
+session: a998acff-af66-4969-a65e-f77cbf5ef8dd
+timestamp: 2026-08-19T00:33:26Z
+git_ref: wkt/tipc_backend_378
+scope: config
+substantive: true
+raw_file: 20260819T003326Z_53516b09_prompt_io.raw.md
+---
+
+## Prompt
+
+Confirm whether the successful TIPC CI leg can become blocking.
+
+## Response summary
+
+Removed the temporary TIPC-only `continue-on-error` expression after
+every refreshed PR #493 check passed.
+
+## Files changed
+
+- `.github/workflows/ci.yml` - make TIPC failures block CI.
+
+## Human edits
+
+The human explicitly requested reconsidering the gate after the CI
+run and chose to leave the generated change local for review before
+requesting this commit plan.

ai/prompt-io/opencode/20260819T003326Z_53516b09_prompt_io.raw.md

@@ -0,0 +1,23 @@
+---
+model: openai/gpt-5.6-sol
+service: opencode
+timestamp: 2026-08-19T00:33:26Z
+git_ref: wkt/tipc_backend_378
+diff_cmd: git diff HEAD~1..HEAD
+---
+
+## Prompt
+
+The user asked whether the now-green TIPC CI leg could stop using
+`continue-on-error`.
+
+## Response
+
+All checks on PR #493 passed, including the Ubuntu TIPC matrix job.
+The generated config change removes the temporary non-blocking gate
+and its obsolete explanatory comment:
+
+> `git diff HEAD~1..HEAD -- .github/workflows/ci.yml`
+
+The remaining matrix, Linux-only exclusion and `modprobe tipc` setup
+stay unchanged.