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docs/pre11-batch-a.md

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+# Pre11 Batch A
+
+This batch performs two mechanical vocabulary alignments:
+
+- `struct erofs_mount.block_bits` is renamed to `blkszbits`.
+- `erofs_fill_map_dev()` is renamed to `erofs_fill_from_devinfo()`.
+
+No types, expressions, control flow, ownership rules, error handling, or runtime behavior were changed. Semantic type alias changes were deferred because they were not needed for this pure mechanical batch.
+
+Validation is limited to identifier occurrence checks, diff inspection, and `git diff --check`. Build and runtime testing are deferred to the later Pre11 validation stage.