feat: begin PR workflow hardening

CHANGELOG.md

@@ -5,6 +5,15 @@
 
 ## Unreleased
 
+### Fixed (PR #308 follow-up)
+
+- The PR workflow hardening follow-ups so `pr-preflight` skips deleted
+  file-targeted inputs, `pr-threads reply` can target an explicit PR context
+  instead of assuming the checkout repo, review-thread batch resolution reports
+  partial progress before failure, GitHub auth-error detection avoids generic
+  `author`-style false positives, and the workflow docs point at the tracked
+  `docs/archive/AGENTS.md` path.
+
 ### Fixed (PR #306 follow-up)
 
 - The Phase 8 runtime-schema/tooling follow-ups so workspace Prettier usage is

Makefile

@@ -7,7 +7,7 @@ SHELL := /bin/bash
 PORT ?= 5173
 BENCH_PORT ?= 8000
 
-.PHONY: hooks verify-ultra-fast verify-fast verify-pr verify-full verify-full-sequential pr-status docs docs-build docs-ci
+.PHONY: hooks verify-ultra-fast verify-fast verify-pr verify-full verify-full-sequential pr-status pr-threads pr-preflight docs docs-build docs-ci
 hooks:
 	@git config core.hooksPath .githooks
 	@chmod +x .githooks/* 2>/dev/null || true
@@ -29,7 +29,13 @@ verify-full-sequential:
 	@VERIFY_LANE_MODE=sequential ./scripts/verify-local.sh full
 
 pr-status:
-	@./scripts/pr-status.sh "$(PR)"
+	@cargo xtask pr-status "$(PR)"
+
+pr-threads:
+	@cargo xtask pr-threads $(ARGS)
+
+pr-preflight:
+	@cargo xtask pr-preflight $(ARGS)
 
 .PHONY: dags dags-fetch
 dags:

docs/workflows.md

@@ -16,7 +16,8 @@ This doc is the “official workflow index” for Echo: how we work, what invari
 
 ### Agent Context System (AI Agents)
 
-AI agents use a **2-tier context system** for seamless handoffs. See [`AGENTS.md`](../AGENTS.md) for full details.
+AI agents use a **2-tier context system** for seamless handoffs. See
+[`docs/archive/AGENTS.md`](./archive/AGENTS.md) for full details.
 
 | Tier      | Store                               | Purpose                                    |
 | --------- | ----------------------------------- | ------------------------------------------ |
@@ -75,8 +76,42 @@ The repo also exposes maintenance commands via `cargo xtask …`:
 - `cargo xtask dags --snapshot-label none` omits snapshot labels (best for CI automation).
 - `cargo xtask dags --snapshot-label rolling` emits a stable `rolling` label.
 - `cargo xtask dags --snapshot-label 2026-01-02` pins a date label (useful for comparisons).
+- `cargo xtask pr-status` summarizes the current PR head, exact unresolved review-thread count, grouped check state, and a concise current-blockers section.
+- `cargo xtask pr-status 306` targets an explicit PR number instead of the current branch PR.
+- `cargo xtask pr-threads list` lists unresolved review threads for the current PR with thread ids, comment ids, path, author, URL, and a short preview.
+- `cargo xtask pr-threads list 306` targets an explicit PR number instead of the current branch PR.
+- `cargo xtask pr-threads reply 123456789 --body-file /tmp/reply.md` posts a human-authored reply to a review comment id on the current branch PR.
+- `cargo xtask pr-threads reply 123456789 --selector 306 --body-file /tmp/reply.md` targets an explicit PR when the review comment belongs to another repo/PR context.
+- `cargo xtask pr-threads resolve --all --selector 306 --yes` resolves all unresolved review threads for a PR after you have verified the fix batch.
+- `cargo xtask pr-threads resolve --yes THREAD_ID_A THREAD_ID_B` resolves explicit GitHub review thread ids when you already know the targets.
+- `cargo xtask pr-preflight` runs the default changed-scope pre-PR gate against `origin/main`.
+- `cargo xtask pr-preflight --full` runs the broader explicit full pre-PR gate.
 - `cargo xtask dind` runs the DIND (Deterministic Ironclad Nightmare Drills) harness locally.
 
+### Pre-PR Preflight
+
+Before opening a PR, run:
+
+```sh
+cargo xtask pr-preflight
+```
+
+What it proves:
+
+- the changed surface passes the normal local `verify-local` PR gate
+- changed Markdown docs pass `markdownlint`, and docs branches also get dead-ref checking
+- runtime schema changes get explicit `pnpm schema:runtime:check`
+- feature-sensitive crates get explicit `--no-default-features` checks
+- maintained shell scripts get a syntax pass via `bash -n`
+
+What it intentionally does **not** prove:
+
+- full CI parity for every matrix lane
+- review-thread state or merge readiness on GitHub
+- human/self-review quality
+
+Use `cargo xtask pr-preflight --full` when you want the broader local proof before a high-risk or cross-cutting PR. `make pr-preflight ARGS='--full'` remains available as a thin alias.
+
 ---
 
 ## Dependency DAG Workflow

package.json

@@ -16,6 +16,7 @@
     "@playwright/test": "^1.48.0",
     "asciichart": "^1.5.25",
     "graphql": "16.11.0",
+    "markdownlint-cli2": "0.22.0",
     "prettier": "3.8.1",
     "vitepress": "1.6.4"
   },