feat: local issue cache and draft-then-push workflow

Replace fetch_issue.py with four scripts around a flat, greppable cache in
tmp/issues/. Planning stays offline and issues reach Gitea in one push:

- issue_get.py: fetch by key or by filter (--milestone/--label/-q). The list
  endpoint carries issue bodies, so a whole milestone costs one request per 50
  issues. Gitea silently ignores an unresolvable milestones= filter and returns
  the entire backlog, so the milestone is resolved up front and every returned
  issue is re-checked locally. --deps walks the dependency graph downwards via
  the structured sections plus native dependencies and writes tree-<slug>.md.
- issue_push.py: validate a local draft against the canonical format, create
  missing labels with the right colors and exclusivity, POST, delete the draft.
- issue_list.py: discovery to stdout, writes nothing.
- issue_index.py: rebuild INDEX.md from what is on disk.

Files use one metadata field per line with inline lists so plain grep works
without a parser. This is a cache and a drafting area, not a mirror: no drift
tracking, no sync back.

Projects are not fetchable — the projects API is 404 on Gitea 1.26; documented
alongside the milestone caveat.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

skills/use/scripts/issue_index.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+"""
+issue_index.py — rebuild tmp/issues/INDEX.md from what is on disk. No network.
+
+The index is a map of the cache, nothing else: issues that were never fetched
+do not appear. issue_get.py and issue_push.py call it automatically; run it by
+hand only after deleting files.
+
+Usage:
+    issue_index.py [--out tmp/issues]
+"""
+import argparse
+import os
+import re
+import sys
+
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+from _tea import ISSUE_ROOT, parse_meta, read_file, write_file  # noqa: E402
+
+
+def cell(v):
+    if isinstance(v, list):
+        return ", ".join(v) or "—"
+    v = (v or "").strip()
+    return v.replace("|", "\\|") or "—"
+
+
+def build(root):
+    rows = []
+    for name in sorted(os.listdir(root)) if os.path.isdir(root) else []:
+        m = re.match(r'^(\d+)\.md$', name)
+        if not m:
+            continue
+        n = int(m.group(1))
+        meta, title, _ = parse_meta(read_file(os.path.join(root, name)))
+        labels = meta.get("labels") or []
+        if isinstance(labels, str):
+            labels = [labels]
+        types = [l for l in labels if l.startswith("type/")]
+        rest = [l for l in labels if not l.startswith("type/")]
+        has_comments = os.path.isfile(os.path.join(root, "%d.comments.md" % n))
+        rows.append({
+            "n": n,
+            "state": cell(meta.get("state")),
+            "type": cell(types[0].split("/", 1)[1] if types else ""),
+            "labels": cell(rest),
+            "title": cell(title),
+            "milestone": cell(meta.get("milestone")),
+            "depends": cell(meta.get("depends")),
+            "comments": ("[%s](%d.comments.md)" % (cell(meta.get("comments")), n)
+                         if has_comments else "—"),
+            "fetched": cell(meta.get("fetched"))[:10],
+        })
+    rows.sort(key=lambda r: r["n"])
+
+    trees = sorted(f for f in (os.listdir(root) if os.path.isdir(root) else [])
+                   if re.match(r'^tree-\d+\.md$', f))
+
+    out = ["# Issue cache", "",
+           "Local cache of fetched issues — not a mirror. Refresh with "
+           "`issue_get.py <n>`; issues absent here were never fetched.", ""]
+    if rows:
+        out += ["| # | state | type | labels | title | milestone | depends | comments | fetched |",
+                "|---|---|---|---|---|---|---|---|---|"]
+        out += ["| [#%d](%d.md) | %s | %s | %s | %s | %s | %s | %s | %s |" % (
+            r["n"], r["n"], r["state"], r["type"], r["labels"], r["title"],
+            r["milestone"], r["depends"], r["comments"], r["fetched"]) for r in rows]
+    else:
+        out.append("_empty_")
+    if trees:
+        out += ["", "## Dependency trees", ""]
+        out += ["- [%s](%s)" % (t, t) for t in trees]
+
+    drafts_dir = os.path.join(root, "drafts")
+    drafts = sorted(f for f in (os.listdir(drafts_dir) if os.path.isdir(drafts_dir) else [])
+                    if f.endswith(".md"))
+    if drafts:
+        out += ["", "## Drafts (not yet pushed)", ""]
+        out += ["- [drafts/%s](drafts/%s)" % (d, d) for d in drafts]
+
+    out.append("")
+    return write_file(os.path.join(root, "INDEX.md"), "\n".join(out)), len(rows)
+
+
+def main():
+    ap = argparse.ArgumentParser(description="Rebuild the issue cache index (no network)")
+    ap.add_argument("--out", default=ISSUE_ROOT, help="cache root (default: tmp/issues)")
+    args = ap.parse_args()
+    path, n = build(args.out)
+    print("%s — %d issue(s)" % (path, n))
+
+
+if __name__ == "__main__":
+    main()