fix(opencode): enforce storage path invariants (#29666)

packages/core/migration/20260601010001_normalize_storage_paths/migration.sql

@@ -0,0 +1,7 @@
+UPDATE project SET worktree = REPLACE(worktree, char(92), '/') WHERE worktree GLOB '[A-Za-z]:' || char(92) || '*' OR worktree LIKE char(92) || char(92) || '%';
+--> statement-breakpoint
+UPDATE project SET sandboxes = REPLACE(sandboxes, char(92) || char(92), '/') WHERE instr(sandboxes, char(92)) > 0 AND (worktree GLOB '[A-Za-z]:*' OR worktree LIKE '//%');
+--> statement-breakpoint
+UPDATE session SET directory = REPLACE(directory, char(92), '/') WHERE directory GLOB '[A-Za-z]:' || char(92) || '*' OR directory LIKE char(92) || char(92) || '%';
+--> statement-breakpoint
+UPDATE session SET path = REPLACE(path, char(92), '/') WHERE path IS NOT NULL AND instr(path, char(92)) > 0 AND (directory GLOB '[A-Za-z]:*' OR directory LIKE '//%');