Documentation that points where the documentation is

The working notes, the roadmap and the eight topic notes now live on the wiki,
so the twelve places in the source that said "see CLAUDE.md" were pointing at
a file this repository no longer has. They say "see the working notes" now,
and the README opens onto the wiki rather than onto two files beside it.

Four references are deliberately untouched -- prompts.py, settings_store.py,
admin/agents.html and the whole of agent/instructions.py. Those name AGENTS.md
and CLAUDE.md as the file an agent chat looks for in *somebody else's* project
directory. Rewriting them would have broken the feature while looking tidy.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/lembas/main.py

@@ -263,7 +263,7 @@ def register_error_handlers(app: FastAPI) -> None:
 
 
 # Flavour lives in error pages, empty states and theme names -- never in the
-# functional UI. See CLAUDE.md.
+# functional UI. See the working notes.
 #
 # The three lines themselves moved into `services/branding.py` with the rest of
 # what an administrator can replace. What is left here is the mapping from a