feat/dossiers-ngi: sticky bar vs-parent loc-on-roots split plus/minus 45rem

scripts/dossiers-ngi/README.md

@@ -58,7 +58,8 @@ Per branch in JSON / sticky bar:
 | `tip_time` | committer time of tip (`%cI`) |
 | `built_at` | when this edition freeze was written |
 | `build_seconds` | wall time of that freeze |
-| `vs_main_plus` / `vs_main_minus` | `git diff --numstat` tip vs **main** tip (sticky bar +grün/−rot; omitted on `main` itself) |
+| `vs_parent_plus` / `vs_parent_minus` | `git diff --numstat` tip vs **parent** tip (sticky bar +grün/−rot; omitted when `parent` is empty or not in the tree, e.g. `main` and `feature/nl-net-injestion-injestor-update`) |
+| `loc` | text-file line count of the tip vs the empty tree (gray `N LOC` in the plus/minus columns; only when there is no parent) |
 
 Rebuild runs **only when** `.edition-tip` ≠ current tip (timer never forces).
 Each run also: `git fetch --prune`, `worktree prune`, drop stale
@@ -105,13 +106,14 @@ rsync -avz --exclude .DS_Store "$SITE/branch-status.json" "$WWW/branch-status.js
 `bar.js` fetches `/branch-status.json` and draws:
 
 ```
-main                         sep01 16:52   8.4s sep30 15:23
-├── feat/sm-content          sep30 16:11  13s sep30 15:23     +N −M
-│   └── feat/website-features …
-└── project_template         sep28 15:03   2.2s sep30 15:23   +N −M
+feature/nl-net-injestion-injestor-update   …   N LOC
+main                                       …   N LOC
+├── feat/sm-content                        …  +N  −M   # vs main
+│   └── feat/website-features              …  +N  −M   # vs sm-content
+└── project_template                       …  +N  −M   # vs main
 ```
 
-Visible cells: name (tree prefix + branch) · tip `monDD HH:MM` · `Ns monDD HH:MM` (build seconds + freeze time) · `+N −M` vs main. No `@sha`, no `default` label (`data-default` stays for flask/cookie). The bar is **viewport-centered**, inner tree `max-width: min(80rem, 100vw − 1.5rem)` (was 45em at 11px ≈ 495px, which clipped long names). Rear cells are right-aligned `tabular-nums`. Poll every 30s **updates when/built/diff in place** when the branch structure is unchanged (no full tree remount).
+Visible cells: name (tree prefix + branch) · tip `monDD HH:MM` · `Ns monDD HH:MM` (build seconds + freeze time) · plus column · minus column. `+N −M` vs the **parent** tip, in two right-aligned columns so `+898` and `+1200` share an edge. Roots with no parent show gray `N` in the plus column and `LOC` in the minus column. No `@sha`, no `default` label (`data-default` stays for flask/cookie). Inner tree `max-width: 45rem` (same as site `#navigation` / `#content` 45em at root 16px), so names line up with About and the minus column with the page edge; below 45rem the tree is full width with a small pad. Rear cells are right-aligned `tabular-nums`. Poll every 30s **updates when/built/plus/minus in place** when the branch structure is unchanged (no full tree remount).
 
 Each name links to `/_cascade/use/<edition>` (cookie + 302 `/`). Caddy map:
 

scripts/dossiers-ngi/branch-status-hourly.py

@@ -258,6 +258,17 @@ def diff_numstat(repo: Path, a: str, b: str) -> tuple[int, int]:
     return plus, minus
 
 
+def empty_tree_oid(repo: Path) -> str:
+    cp = git(repo, "hash-object", "-t", "tree", "/dev/null")
+    return (cp.stdout or "").strip()
+
+
+def loc_at_tip(repo: Path, tip: str, empty: str) -> int:
+    """Text-file line count of tip vs the empty tree."""
+    plus, _ = diff_numstat(repo, empty, tip)
+    return plus
+
+
 def tip_commit_time(repo: Path, tip: str) -> str:
     """Committer ISO time of tip (empty on failure)."""
     cp = git(repo, "log", "-1", "--format=%cI", tip, check=False)
@@ -564,10 +575,7 @@ def build_payload(repo: Path, tips: dict[str, str], rebuild: bool) -> dict:
             sync_flask_alias(ed_root, tips)
 
     tip_times = {name: tip_commit_time(repo, tip) for name, tip in tips.items()}
-    main_tip = tips.get("main", "")
-    vs_main = {
-        name: diff_numstat(repo, main_tip, tip) for name, tip in tips.items()
-    }
+    empty = empty_tree_oid(repo)
     branches_out = []
     for row in rows:
         name = row["branch"]
@@ -593,11 +601,14 @@ def build_payload(repo: Path, tips: dict[str, str], rebuild: bool) -> dict:
             entry["built_at"] = meta["built_at"]
         if "build_seconds" in meta:
             entry["build_seconds"] = meta["build_seconds"]
-        # sticky bar: +grün / −rot vs main (omit on main itself)
-        if name != "main" and main_tip:
-            plus, minus = vs_main.get(name, (0, 0))
-            entry["vs_main_plus"] = plus
-            entry["vs_main_minus"] = minus
+        # sticky bar: +grün/−rot vs parent tip; gray loc when no parent in tree
+        parent = row["parent"]
+        if parent and parent in tips:
+            plus, minus = diff_numstat(repo, tips[parent], row["tip"])
+            entry["vs_parent_plus"] = plus
+            entry["vs_parent_minus"] = minus
+        else:
+            entry["loc"] = loc_at_tip(repo, row["tip"], empty)
         branches_out.append(entry)
 
     payload = {