session-memory: weekly retro entrypoint + hub publish (AGENTIC-WP-0010)

The analysis half of the weekly coding retrospection. retro/build.py: windowed
detect+measure -> top-3 improvement suggestions per repo (cross-flavor first,
recommendations pulled from the Pattern Catalog) + fleet snapshot. retro/publish.py:
publishes the report to the hub as the coding_retro read model (event_type=
coding_retro progress event) + local JSON/md, graceful degrade. retro entrypoint
with --window-days/--publish/--json. Live verify over real sessions surfaced
per-repo suggestions with catalog recommendations. 13 new tests; suite 152/152.

Consumed by activity-core ACTIVITY-WP-0008 (Weekly Coding Retrospection, Sat 19:00).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

session_memory/retro/publish.py

@@ -0,0 +1,78 @@
+"""Publish the weekly retro (AGENTIC-WP-0010 T02).
+
+The retro is published to the State Hub as a **read model** — a progress event of
+``event_type=coding_retro`` whose ``detail`` carries the structured report. This is
+exactly how ``daily-triage-report`` surfaces, and it is what activity-core's
+``coding_retro`` resolver (ACTIVITY-WP-0008) reads. A local JSON + markdown report
+is always written; the hub publish is best-effort and **degrades gracefully** when
+the hub is unreachable.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import urllib.request
+from typing import Callable, Optional
+
+DEFAULT_HUB = "http://127.0.0.1:8000"
+
+
+def render_markdown(report: dict) -> str:
+    w = report.get("window", {})
+    lines = [
+        f"# Weekly Coding Retro  ({w.get('since', '')[:10]} → {w.get('until', '')[:10]})",
+        f"_{report.get('n_sessions', 0)} real sessions · generated {report.get('generated_at', '')}_",
+        "",
+        "## Top improvement suggestions (cross-flavor first, ≤3 per repo)",
+    ]
+    if not report.get("suggestions"):
+        lines.append("- (no recurring problems above threshold this week)")
+    for s in report.get("suggestions", []):
+        flag = " [CROSS-FLAVOR]" if s.get("cross_flavor") else ""
+        lines.append(f"- **{s['repo']}** ({s['priority']}, score={s['score']}){flag}: "
+                     f"{s['title']} — {s['recommendation']}")
+    m = report.get("measure", {})
+    lines += ["", "## Fleet snapshot",
+              f"- infra-overhead median: {m.get('infra_overhead_share_median')}",
+              f"- error rate: {m.get('error_rate')}  ·  schema-thrash: {m.get('schema_thrash_sessions')}",
+              f"- success rate: {m.get('success_rate')}  ·  tokens p50: {m.get('tokens_p50')}"]
+    return "\n".join(lines)
+
+
+def write_local(report: dict, json_path: str, md_path: Optional[str] = None) -> None:
+    os.makedirs(os.path.dirname(json_path) or ".", exist_ok=True)
+    with open(json_path, "w", encoding="utf-8") as fh:
+        json.dump(report, fh, indent=2, sort_keys=True)
+        fh.write("\n")
+    if md_path:
+        with open(md_path, "w", encoding="utf-8") as fh:
+            fh.write(render_markdown(report))
+            fh.write("\n")
+
+
+def _http_post(url: str, payload: dict) -> None:
+    req = urllib.request.Request(url, data=json.dumps(payload).encode(),
+                                 headers={"Content-Type": "application/json"}, method="POST")
+    with urllib.request.urlopen(req, timeout=10) as r:
+        r.read()
+
+
+def publish_to_hub(report: dict, *, base_url: str = DEFAULT_HUB,
+                   poster: Optional[Callable[[str, dict], None]] = None) -> bool:
+    """POST the retro as an event_type=coding_retro progress event. Best-effort."""
+    poster = poster or _http_post
+    n = report.get("n_sessions", 0)
+    k = len(report.get("suggestions", []))
+    payload = {
+        "event_type": "coding_retro",
+        "author": "helix-forge",
+        "summary": f"Weekly coding retro: {k} ranked suggestions across "
+                   f"{report.get('window', {}).get('days', 7)} days ({n} sessions).",
+        "detail": report,
+    }
+    try:
+        poster(f"{base_url.rstrip('/')}/progress/", payload)
+        return True
+    except Exception:
+        return False