docs(retrieval): stop asking the operator to diagnose retrieval (#4102)

The last item in this step's done-when: no wording anywhere asks an
operator to tune for correctness.

Four Settings hints told them to do exactly that — "raise it if rules
keep arriving unread", "lower it if a git push arrives with nothing",
"lower this if genuine duplicates go unnoticed". Every one of those
asks the operator to diagnose a ranker from symptoms, which is the job
the model now does from the records: the telemetry says what each bar
refused, and reading those records is what separates a real miss from
a bar doing its job. The hints keep the explanation of WHAT each number
is — that is worth reading — and drop the homework.

`plugin_context.py` said the defaults "are meant to be tuned from
retrieval_logs once data accrues", which was true and had no owner.
It now names who does it and with what.

`retrieval_telemetry`'s docstring gained the warning that belongs
beside it: this readout has been measured pointing the wrong way, so
the ids it returns are the point, not its percentiles.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy

frontend/src/views/SettingsView.vue

@@ -1605,9 +1605,9 @@ async function deleteUser(userId: number) {
             Stricter than the prompt threshold above on purpose. Any two pieces of
             code look somewhat alike — shared keywords, indentation, structure — so
             resemblance scores start higher for code than for prose, and a bar tuned
-            for prompts flags unrelated code as prior art. Lower this if genuine
-            duplicates go unnoticed; raise it if you're being offered snippets that
-            have nothing to do with what's being written. Snippets recorded at the
+            for prompts flags unrelated code as prior art. Claude keeps this
+            one current from what the arm actually surfaced and refused; set it
+            yourself if you disagree with where it has landed. Snippets recorded at the
             exact file are always shown regardless — those are prior art by
             location, not by resemblance.
           </p>
@@ -1644,8 +1644,9 @@ async function deleteUser(userId: number) {
             preloaded any more, so this is the only way a rule reaches a write.
             Stricter than the threshold above, because there are far fewer rules
             than snippets: with a small set something always ranks first, so the
-            bar has to carry more of the judgement. Raise it if rules keep
-            arriving unread; lower it if a rule you needed never showed up.
+            bar has to carry more of the judgement. If rules arrive unread, or one
+            you needed never showed up, that is Claude's to notice and correct
+            from the telemetry — and the budget below is usually the better lever.
           </p>
         </div>
         <div class="field">
@@ -1679,8 +1680,7 @@ async function deleteUser(userId: number) {
             query is the command text rather than code. Lower than the one above
             on purpose: a shell command is short, so it scores lower for the same
             relevance — at a shared bar this arm spoke on 2% of calls against the
-            write path's 37%. Raise it if commands attract rules that do not
-            apply; lower it if a <code>git push</code> arrives with nothing.
+            write path's 37%.
           </p>
         </div>
         <div class="field">
@@ -1748,9 +1748,9 @@ async function deleteUser(userId: number) {
             written</em>, looked up when a task closes. Unlike every other bar
             here, the question this arm asks never changes — so its score is
             fixed by your preferences alone, and it will either always find one
-            or never find one. If you have written a preference for report shape
-            and it is not arriving, lower this; there is no run of calls that
-            will reveal the problem on its own.
+            or never find one, and no run of calls will reveal a dead one on its
+            own. That is why this arm is worth looking up in the panel below when
+            a report preference never seems to arrive.
           </p>
         </div>
         <div class="field">