Archive the last two completed OpenSpec changes

[Aaronontheweb]

Why

PR #2024 archived 16 completed changes and left two for a maintainer call. The
maintainer approved both for archive. This PR syncs their delta specs and
archives them.

No .cs file changes. openspec list shows 5 active changes.
openspec validate --all passes (75 items). dotnet slopwatch analyze reports
0 issues.

Archived changes

Each change moves to openspec/changes/archive/2026-08-19-<name>/.

Change	Merged PRs
surface-reminder-schedule-failures	#1886
redirect-shared-temp-to-session-scratch	#1890, #1925, #1926, #1945, #1956

Spec syncs

redirect-shared-temp-to-session-scratch

The OpenSpec CLI applied both delta files:

• openspec/specs/session-cwd/spec.md — adds "Session directory is the private
  shell scratch location" and modifies "Shell tool failure-path hint for cwd
  outside safe spaces".
• openspec/specs/tool-approval-gates/spec.md — adds "Platform temporary scope
  receives a session-scratch correction", "Intentional platform-temp retry
  reaches ordinary approval", and "Parent and subagent scratch corrections are
  equivalent".

surface-reminder-schedule-failures

PR #2024 already rewrote "Failure handling and guardrails" in
openspec/specs/netclaw-scheduling/spec.md from the
reliable-one-shot-reminder-retry delta, with corrections against the merged
code. A programmatic apply would undo those corrections, so this delta was
merged by hand. The added content is:

• An execution failure and a scheduling failure share one ConsecutiveFailures
  count.
• A successful reschedule alone does not reset the count. The post-fire cron
  reschedule runs before that occurrence executes.
• An unattended reschedule site — the post-fire reschedule and the startup
  reconcile restore loop — emits ReminderScheduleFailed at Warning severity.
  On the threshold it disables the reminder, emits ReminderAutoDisabled at
  Critical severity, and posts a channel notice.
• No silent UTC fallback and no silent skip.
• The set_reminder create path and update path return the error to the caller
  and emit no alert.

Three delta claims are stale against ReminderManagerActor on dev and were
dropped:

• The delta says "auto-pause" with status: "paused" in tasks.json. The
  merged code sets Enabled = false and TerminalOutcome = Failed. The
  corrected "disable" wording from PR Archive completed OpenSpec changes and sync their specs #2024 stands.
• The delta names an ExecutionTimeoutSeconds constant on
  ReminderExecutionActor. No such constant exists. The one-hour absolute limit
  stands.
• The delta repeats execution-failure, reset, concurrency, and timeout scenarios
  that PR Archive completed OpenSpec changes and sync their specs #2024 already corrected. The corrected scenarios stand.

Task checkboxes

Task 4.3 of redirect-shared-temp-to-session-scratch is now ticked. It asked
for native Windows coverage of path and PowerShell behavior. The full
pr_validation suite ran green on Windows against current dev on 2026-08-20,
from branch feature/windows-validation-run. That branch is deleted now.

These boxes stay unticked, per the maintainer's acceptance:

• surface-reminder-schedule-failures tasks 4.5 and 4.6 — parked test tasks.
  The maintainer accepts them as guaranteed by construction. No reset code was
  added at the reschedule sites, and the post-fire path calls the same
  ReportScheduleFailureAsync that the reconcile tests exercise.
• surface-reminder-schedule-failures task 6.4 — ./evals/run-evals.sh needs
  eval-target credentials. The maintainer accepts this as an eval-credentials
  gap.
• redirect-shared-temp-to-session-scratch task 4.4 — the same eval gate blocks
  the last item of this task.

Remaining active changes

• memory-core-redesign (4/54)
• reduce-fresh-session-approval-spam (69/75)
• streaming-tool-call-execution (33/38)
• subagent-explicit-model-selection (0/24)
• memory-relevance-gate (0/14)