docs: auto-generate Makefile reference page for RTD

Adds a Sphinx extension at docs/_source/_ext/makefile_targets.py that
parses the project Makefile's '## description' annotations and writes
docs/_source/api/makefile.rst at build time. Same convention 'make help'
uses, so the reference stays in sync with the source.

Generated page is grouped by target prefix (fetch-, ingest-, distill-,
docs-, etc.) and rendered as a list-table. Shows on RTD alongside the
autodoc API modules.

Generated file is gitignored — RTD regenerates on every build.

.gitignore

@@ -21,3 +21,6 @@ bench/qa_results/
 
 # Sphinx build artifacts (generated; RTD builds on its servers)
 docs/_source/_build/
+
+# Auto-generated by docs/_source/_ext/makefile_targets.py at Sphinx build time
+docs/_source/api/makefile.rst

docs/_source/_ext/makefile_targets.py

@@ -0,0 +1,74 @@
+"""Generate docs/_source/api/makefile.rst from Makefile ## annotations.
+
+Convention: every documented target has the form
+    target-name: deps ## one-line description
+
+This extension parses the project's Makefile and writes an RST page
+listing every documented target, grouped by category prefix.
+"""
+
+from pathlib import Path
+import re
+
+TARGET_RE = re.compile(r"^([a-zA-Z0-9_-]+):.*?##\s*(.*)$")
+
+
+def parse_makefile(makefile_path: Path) -> list[tuple[str, str]]:
+    """Return list of (target, description) tuples from a Makefile."""
+    targets = []
+    for line in makefile_path.read_text(encoding="utf-8").splitlines():
+        m = TARGET_RE.match(line)
+        if m:
+            targets.append((m.group(1), m.group(2).strip()))
+    return targets
+
+
+def categorize(targets: list[tuple[str, str]]) -> dict[str, list[tuple[str, str]]]:
+    """Group targets by leading prefix (e.g. 'fetch-', 'ingest-', 'docs-')."""
+    groups: dict[str, list[tuple[str, str]]] = {}
+    for name, desc in targets:
+        prefix = name.split("-", 1)[0] if "-" in name else name
+        groups.setdefault(prefix, []).append((name, desc))
+    return groups
+
+
+def generate_rst(targets: list[tuple[str, str]], output_path: Path) -> None:
+    """Write a single RST page listing every documented target."""
+    groups = categorize(targets)
+    lines = [
+        "Makefile reference",
+        "==================",
+        "",
+        "Every aborist workflow lives behind a ``make`` target. This page is",
+        "auto-generated from the project ``Makefile``'s ``## description``",
+        "annotations at Sphinx build time, so it stays in sync with the source.",
+        "",
+        "Run ``make help`` locally for the same listing.",
+        "",
+    ]
+    for prefix in sorted(groups):
+        lines.append(prefix)
+        lines.append("-" * len(prefix))
+        lines.append("")
+        lines.append(".. list-table::")
+        lines.append("   :widths: 25 75")
+        lines.append("   :header-rows: 1")
+        lines.append("")
+        lines.append("   * - Target")
+        lines.append("     - Description")
+        for name, desc in sorted(groups[prefix]):
+            lines.append(f"   * - ``{name}``")
+            lines.append(f"     - {desc}")
+        lines.append("")
+    output_path.write_text("\n".join(lines), encoding="utf-8")
+
+
+def setup(app):
+    """Sphinx hook: regenerate makefile.rst at the start of every build."""
+    project_root = Path(app.srcdir).parent.parent
+    makefile = project_root / "Makefile"
+    output = Path(app.srcdir) / "api" / "makefile.rst"
+    if makefile.exists():
+        targets = parse_makefile(makefile)
+        generate_rst(targets, output)
+    return {"version": "1.0", "parallel_read_safe": True}

docs/_source/conf.py

@@ -3,9 +3,10 @@
 import sys
 from pathlib import Path
 
-# Add aborist package to path
+# Add aborist package + local _ext (Sphinx extensions) to path
 project_root = Path(__file__).parent.parent.parent
 sys.path.insert(0, str(project_root))
+sys.path.insert(0, str(Path(__file__).parent / "_ext"))
 
 # Project info
 project = "Aborist"
@@ -20,6 +21,7 @@ extensions = [
     "sphinx.ext.napoleon",
     "sphinx.ext.intersphinx",
     "sphinx.ext.viewcode",
+    "makefile_targets",  # local: generates api/makefile.rst from Makefile ## annotations
 ]
 
 # Autodoc settings

docs/_source/index.rst

@@ -9,6 +9,7 @@ Contents:
    :maxdepth: 3
    :caption: API Modules
 
+   api/makefile
    api/substrate
    api/storage
    api/retrieval