refactor(mcp): trim the save_finding description to the style budget

src/ClaudeDo.Worker/External/FindingsMcpTools.cs

@@ -21,16 +21,11 @@ public sealed class FindingsMcpTools
     }
 
     [McpServerTool, Description(
-        "Record a durable trap or invariant you just learned about this codebase, so future sessions " +
-        "read it instead of rediscovering it — call it the moment you notice one, not at the end of " +
-        "the session. Admission bar (all three must hold, or don't save it): lasting (still true next " +
-        "week), non-obvious (a competent reader would get it wrong), and behaviour-changing (\"X looks " +
-        "like Y but is Z — do W instead\"). A bug you fixed is not a finding, that is git history; " +
-        "neither is a design decision or a status update. Findings are a scarce, curated list, not a " +
-        "log — when unsure, don't save it. Re-using a slug overwrites that finding. This is a dumb " +
-        "write: it does not read the code or generate the finding for you, you already have the " +
-        "context. nearCapacity=true in the result means the index is getting too long to stay cheap — " +
-        "prune stale entries before adding more.")]
+        "Record a durable trap you just learned about this codebase, so future sessions read it " +
+        "instead of rediscovering it. Save only what is lasting, non-obvious and behaviour-changing " +
+        "(\"X looks like Y but is Z — do W instead\"); a bug you fixed is git history, not a finding. " +
+        "When unsure, don't. Re-using a slug overwrites it. nearCapacity=true means the index is " +
+        "getting too long to stay cheap — prune before adding more.")]
     public async Task<SaveFindingResult> SaveFinding(
         [Description("Stable lowercase kebab-case id, max 60 chars, e.g. 'conpty-arg-quoting'. Same slug overwrites.")] string slug,
         [Description("One full sentence stating the trap itself — this is the index line other agents scan.")] string title,