docs: anchor the product-doc citations to symbols, not line numbers

Ten more were already pointing at unrelated code. Vendor SDK and SWELL citations left alone — those files don't move.

src/core/package/CLAUDE.md

@@ -187,7 +187,7 @@ append-only rule and the per-fixture inventory.
   hostile/older package declaring one is not this track's concern).
 - **`import_plan`'s `spelledLikeABankFile` mints a fresh name even with NO
   collision, and that third condition is a deliberate decision, not spec-derived.**
-  `docs/product/bank-package.md:447` ties the auto-rename mint to a *collision*
+  `docs/product/bank-package.md` §"Identity and collision on import" (collision rule 2) ties the auto-rename mint to a *collision*
   only; `spelledLikeABankFile` additionally mints whenever the package's own name
   isn't spelled the way `deriveBankPaths` spells one (extension, sanitized stem).
   Kept for two reasons: uniform folder spelling for every landed file regardless of
@@ -195,4 +195,4 @@ append-only rule and the per-fixture inventory.
   filename or carries an unexpected extension (e.g. `evil.exe`) lands sanitized
   (`evil_<tag>.wav`) rather than verbatim. `ImportPlan` counts this separately from a
   genuine folder-name collision (`sanitizeRenameCount` vs `collisionRenameCount`) so
-  the summary line means what `bank-package.md:447` says it means.
+  the summary line means what `bank-package.md` §"Identity and collision on import" (collision rule 2) says it means.