refactor: remove the dead state-to-todo mapping subsystem

`pearl-state-to-todo-mapping` and its derived regex stopped doing real work once keyword rendering moved to slugifying the Linear state name (`pearl--state-name-to-keyword`) and the keyword-to-state direction moved to resolving through the team's workflow states. The defcustom fed only `pearl--get-todo-states-pattern`, which had no caller left, and the two cache vars existed only to serve that dead function. State extraction reads `org-get-todo-state` off the buffer's `#+TODO` line, so nothing live touched the mapping.

I removed the defcustom, both cache vars, and the dead function, and dropped the three pattern tests that exercised it. Removing the defcustom orphaned the mapping bindings that ~12 test setup macros still carried. They were passing through slugification rather than the map, so I stripped them too and kept the `org-todo-keywords` bindings the temp buffers actually need. Also dropped the stale README config row.

1 files changed, 3 insertions, 8 deletions

diff --git a/tests/test-pearl-format.el b/tests/test-pearl-format.el
index ece64d3..96ec395 100644
--- a/tests/test-pearl-format.el
+++ b/tests/test-pearl-format.el
@@ -32,15 +32,10 @@
 (require 'testutil-fixtures (expand-file-name "testutil-fixtures.el"))
 
 (defmacro test-pearl--with-default-mapping (&rest body)
-  "Run BODY with the default state mapping and a clean pattern cache."
+  "Run BODY.  Kept as a thin wrapper: the renderer slugifies the state name now,
+so these tests no longer need a state mapping bound."
   (declare (indent 0))
-  `(let ((pearl-state-to-todo-mapping
-          '(("Todo" . "TODO") ("In Progress" . "IN-PROGRESS")
-            ("In Review" . "IN-REVIEW") ("Backlog" . "BACKLOG")
-            ("Blocked" . "BLOCKED") ("Done" . "DONE")))
-         (pearl-todo-states-pattern nil)
-         (pearl--todo-states-pattern-source nil))
-     ,@body))
+  `(progn ,@body))
 
 (defun test-pearl--norm-full ()
   "A normalized fully-populated issue."