Require the Assisted-by trailer on every agent-written commit

The previous wording described what an AI-assisted commit looks like
without saying the trailer is mandatory, which left it readable as a
convention for substantial changes only. The marker is what lets a
reader tell which work came from an agent, so it has to hold across all
of it -- an exemption for trivial commits makes the absence of the
trailer meaningless. The same reasoning closed a matching gap in how
agents comment on PRs, where a single disclaimer on a review body left
eleven inline comments unmarked.

Assisted-by: Claude:claude-opus-5[1m]:Claude Code

CLAUDE.md

@@ -84,7 +84,8 @@ Solutions & filters: `ILSpy.sln` builds everything; `ILSpy.XPlat.slnf` is the de
 - **Body explains the *why*** and the non-diff context only: the constraint, the prior incident, the decision, what was tried and rejected, the invariant that motivated the change. Keep it short — one short paragraph is usually enough. The diff already shows the *what* — don't restate it, and don't enumerate per-file changes.
 - `Fix #NNNN: ...` closes an issue. `#NNNN` references one without closing.
 - **en-US English** in subject and body. ASCII-only unless a non-ASCII character is genuinely required for what the message describes.
-- **AI attribution: use `Assisted-by:`, not `Co-Authored-By:`.** Following the Linux kernel's coding-assistants guidance (https://docs.kernel.org/process/coding-assistants.html#attribution), an AI-assisted commit ends with a trailer of the form `Assisted-by: AGENT_NAME:MODEL_VERSION:HARNESS` — agent, model id, and the harness that ran it, colon-separated, e.g. `Assisted-by: Claude:claude-opus-4-8:Claude Code`. Use the session's actual model id and harness. Don't list analysis/build tools. Do **not** add a `Co-Authored-By:` line for the AI, and an AI agent **must not** add a `Signed-off-by:` (only a human can certify the DCO).
+- **AI attribution is mandatory on every commit an agent writes: use `Assisted-by:`, not `Co-Authored-By:`.** Following the Linux kernel's coding-assistants guidance (https://docs.kernel.org/process/coding-assistants.html#attribution), such a commit ends with a trailer of the form `Assisted-by: AGENT_NAME:MODEL_VERSION:HARNESS` — agent, model id, and the harness that ran it, colon-separated, e.g. `Assisted-by: Claude:claude-opus-4-8:Claude Code`. Use the session's actual model id and harness. Don't list analysis/build tools. Do **not** add a `Co-Authored-By:` line for the AI, and an AI agent **must not** add a `Signed-off-by:` (only a human can certify the DCO).
+- **There is no exemption from the trailer.** It goes on every commit the agent authors — one-liners, formatting, reverts, rebases that reword, and changes the human dictated word for word. The same holds anywhere else an agent writes under a human's account, such as PR and issue comments, where every individual comment carries the disclosure rather than one summary covering a batch. A rule with an exemption for the common case stops being a rule: a reader can only tell which work came from an agent if the marker is on all of it. An agent-written commit missing the trailer is a defect — amend it, don't leave it.
 
 ## Changes to the decompiler engine