[PATCH] Documentation: coding-assistants: add optional Acted-By: trailer

[Blake Morrison <blake@truealter.com>]

The existing policy correctly separates AI tool attribution
(Assisted-by:) from legal accountability (Signed-off-by:). In practice,
contributors increasingly work across pseudonymous and legal-name
contexts, and a third slot -- identifying the human sovereign identity
under which the work was performed -- lets downstream tooling (CI,
provenance trackers, identity systems) bind a commit to a stable handle
without disturbing the DCO.

Add Acted-By: as an optional, informational companion trailer. It does
not replace Signed-off-by:, does not change DCO requirements, and does
not mandate any format; the out-of-tree
draft-morrison-identity-attributed-commits defines one such scheme, but
contributors are free to use any handle form they prefer.

The three trailers then map cleanly:

  * Assisted-by:    -- what tool drafted this
  * Acted-By:       -- who the human was, as a handle
  * Signed-off-by:  -- legal DCO attestation

This mirrors the informal separation already present in commits that
carry both a pseudonymous Reported-by: and a separate Signed-off-by:.

Signed-off-by: Blake Morrison <blake@truealter.com>
---
 Documentation/process/coding-assistants.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/process/coding-assistants.rst b/Documentation/process/coding-assistants.rst
index 899f4459c..b1d2d2f66 100644
--- a/Documentation/process/coding-assistants.rst
+++ b/Documentation/process/coding-assistants.rst
@@ -57,3 +57,16 @@ Basic development tools (git, gcc, make, editors) should not be listed.
 Example::
 
   Assisted-by: Claude:claude-3-opus coccinelle sparse
+
+Contributors may optionally add an ``Acted-By:`` tag identifying the
+human sovereign identity under which the work was performed, in a form
+stable across pseudonymous and legal-name contexts::
+
+  Acted-By: handle
+
+``Acted-By:`` is informational. It does not replace ``Signed-off-by:``;
+DCO attestation remains mandatory. Where ``Assisted-by:`` identifies
+*what tooling* contributed, ``Acted-By:`` identifies *who* the human
+was, as a stable handle. Handle format is out of scope for this
+document; draft-morrison-identity-attributed-commits in the IETF
+document stream describes one such scheme.
-- 
2.53.0