feat: path budget - a file's path stays at 160 characters or fewer; new, rename, move and raw accept refuse more, lint reports Long Paths (#163)

Files changed:
- CHANGES.md
- README.md
- VERSION
- instructions/page-lifecycle.md
- kb/CONTRACT.md
- tools/CONTRACT.md
- tools/chemenu/commands/_util.py
- tools/chemenu/commands/lint.py
- tools/chemenu/commands/new_page.py
- tools/chemenu/commands/page_ops.py
- tools/chemenu/commands/raw_cmd.py
- tools/chemenu/lint_core.py
- tools/chemenu/tests/test_lint.py
- tools/chemenu/tests/test_new_page.py
- tools/chemenu/tests/test_page_ops.py
- tools/chemenu/tests/test_raw_cmd.py
- tools/chemenu/tests/test_titles.py
- tools/chemenu/titles.py

tools/chemenu/commands/raw_cmd.py

@@ -72,7 +72,7 @@ from typing import Optional
 import typer
 
 from chemenu import cli_contract, config
-from chemenu.commands._util import fail, rel_path, success
+from chemenu.commands._util import check_path_budget, fail, rel_path, success
 from chemenu.frontmatter_io import write_page
 from chemenu.kb_scan import load_kb_pages
 from chemenu.provenance import citing_pages, source_pages_by_raw_file, source_raw_files
@@ -371,9 +371,12 @@ def _replace(
         cli_contract.Failure(
             label="raw accept",
             cause="A file does not exist, is not under `incoming/`, or is nested more than one "
-            "level below it; two files in one call share a filename; or a target path already "
-            "exists",
-            reaction="Fix the named argument and retry once",
+            "level below it; two files in one call share a filename; a target path already "
+            "exists; or a target path would be over the path budget (160 UTF-16 code units "
+            "below the instance root)",
+            reaction="Fix the named argument and retry once. For a path over the budget, "
+            "rename the file in `incoming/` to something shorter - the refusal comes before "
+            "anything moves, so `incoming/` and `raw/` are unchanged",
         ),
         cli_contract.Failure(
             label="raw accept",
@@ -562,6 +565,11 @@ def raw_accept_command(
         moves.append((new_path, dst))
 
     for _src, dst in moves:
+        check_path_budget(
+            dst,
+            "The name comes from the file in incoming/: rename it there to something shorter "
+            "and accept it again.",
+        )
         if dst.exists():
             fail(f"Cannot promote: {rel_path(dst)} already exists.")