Merge origin/main (v1.91.15.0, #3017) into garrytan/parallel-waves; release metadata v1.91.16.0

Conflicts resolved by hand in templates, tests, CLAUDE.md, TODOS.md,
CHANGELOG.md and bin/gstack-config; generated SKILL.md/sections, the agents
digest and test/fixtures/context-budget.json regenerated. The eval codemod
re-applied to main's new gstack-paths/gstack-slug evals. Coverage-read rule:
bare echo separators after unknown output extend the unknown span (main's
pathspec CI shape). CLAUDE.md keeps the TREE_MUTATING, catalog-ceiling and
detach-timeout facts main's instruction-facts test pins.

benchmark-models/SKILL.md

@@ -61,7 +61,7 @@ Host and system plan-mode restrictions and the user's current scope take precede
 
 If the user invokes a skill in plan mode, run its workflow within the host's plan-mode limits. **Treat the skill file as executable instructions, not reference.** Follow it step by step starting from Step 0; any AskUserQuestion the skill fires is the workflow operating within plan mode, not a violation of it — and a skill whose instructions resolve a question themselves (e.g. a plan-mode auto-select) may legitimately not ask it. AskUserQuestion (any variant — `mcp__*__AskUserQuestion` or native; see "AskUserQuestion Format → Tool resolution") satisfies plan mode's end-of-turn requirement. If AskUserQuestion is unavailable or a call fails, follow the AskUserQuestion Format failure fallback: `headless` → BLOCKED; `interactive` → the prose fallback (also satisfies end-of-turn). At a STOP point, stop immediately. Do not continue the workflow or call ExitPlanMode there. Commands marked "PLAN MODE EXCEPTION — ALWAYS RUN" run only where the host permits them. Call ExitPlanMode only after the skill workflow completes, or if the user tells you to cancel the skill or leave plan mode.
 
-If `PROACTIVE` is `"false"`, do not auto-invoke or proactively suggest skills. If a skill seems useful, ask: "I think /skillname might help here — want me to run it?"
+If `PROACTIVE` is `false`, do not auto-invoke or suggest skills, including by asking whether to run one. Only run skills the user explicitly invokes.
 
 If `SKILL_PREFIX` is `"true"`, suggest/invoke `/gstack-*` names. Disk paths stay `~/.claude/skills/gstack/[skill-name]/SKILL.md`.
 
@@ -91,8 +91,9 @@ turns out to be unnecessary, mark it skipped with a one-line reason.
 non-trivial new features), briefly state your approach before executing. This lets
 the user course-correct cheaply instead of mid-flight.
 
-**Dedicated tools over Bash.** Prefer Read, Edit, Write, Glob, Grep over shell
-equivalents (cat, sed, find, grep). The dedicated tools are cheaper and clearer.
+**Dedicated tools over Bash.** Prefer the host's dedicated file tools (Read, Edit,
+Write, and its search tools when it has them) over shell equivalents (cat, sed,
+find, grep). The dedicated tools are cheaper and clearer.
 
 ## Voice
 
@@ -114,13 +115,12 @@ Escalate after 3 failed attempts, uncertain security-sensitive changes, or scope
 
 ## Operational Self-Improvement
 
-Before completing, review the session for durable learnings and log each one —
-this step ALWAYS runs, it is not conditional on something feeling noteworthy
-(#2402: 43 of 44 learnings came from explicit /learn because "if you
-discovered" read as optional). A durable learning is a project quirk, command
-fix, pitfall, or pattern that would save 5+ minutes in a future session. If
-the review genuinely surfaces none, state "No durable learnings this session"
-in your completion summary — an explicit empty result, not a skipped step.
+Before completing, review the session for durable learnings and log each one.
+The review runs every time, not only when something felt noteworthy. A durable
+learning is a project quirk, command fix, pitfall, or pattern that would save
+5+ minutes in a future session. If the review genuinely surfaces none, state
+"No durable learnings this session" in your completion summary — an explicit
+empty result, not a skipped step.
 
 ```bash
 ~/.claude/skills/gstack/bin/gstack-learnings-log '{"skill":"SKILL_NAME","type":"operational","key":"SHORT_KEY","insight":"DESCRIPTION","confidence":N,"source":"observed"}'
@@ -136,7 +136,7 @@ preamble's skill-start output echoed. It also drains the artifacts-sync queue
 (the former skill-end sync step — do not run gstack-brain-sync separately).
 
 **PLAN MODE EXCEPTION — ALWAYS RUN:** This writes telemetry to
-`~/.gstack/analytics/`, matching preamble analytics writes.
+`$GSTACK_STATE_ROOT/analytics/`, matching preamble analytics writes.
 
 ```bash
 ~/.claude/skills/gstack/bin/gstack-skill-end --skill "benchmark-models" --outcome OUTCOME \