fix(schema): remove '; ' from comment that broke ddl.split(';') statement extractor

pg_schema.py:1320 splits DDL strings naively on ';'. The comment block
above workflow_graph_layout had a semicolon inside the comment text:

  -- ... topology_fingerprint tracks which graph build the
  -- coordinates were computed against; the tile + quadtree endpoints

The split produced a stray 'the tile + quadtree endpoints' statement
that PG failed with: syntax error at or near 'the'. Caught when E1
ablation logged 'Schema statement failed' on every benchmark restart.

Reworded the comment to use a sentence boundary instead of a
semicolon. Schema now parses cleanly; verified by enumerating
get_all_ddl() and grepping all DDL-block comments for residual ';'.

Author: cdeust

mcp_server/infrastructure/pg_schema.py

@@ -492,7 +492,7 @@
 -- igraph DrL on CPU) and persists the result here so the viz can ship
 -- coordinates with each node — eliminating the d3-force tick cost in
 -- the browser. ``topology_fingerprint`` tracks which graph build the
--- coordinates were computed against; the tile + quadtree endpoints
+-- coordinates were computed against. The tile and quadtree endpoints
 -- read them by ``layout_version`` so a stale layout never serves
 -- alongside fresh nodes.
 CREATE TABLE IF NOT EXISTS workflow_graph_layout (