fix(review): address PR #910 review feedback

- container.rs: warn on kubectl JSON parse failure instead of silent fallback
- runner.rs: fix savings inflation when filter_stdout_only by tracking stdout only
- README.md: document automod behavior in module registration step

Author: aeppling

src/cmds/README.md

@@ -189,7 +189,7 @@ Adding a new filter or command requires changes in multiple places. For TOML-vs-
    - Add `.tee("label")` when the filter parses structured output (enables raw output recovery on failure)
    - **Exit codes**: handled automatically by `run_filtered()` — just return its result
 2. **Register module**:
-   - Add `pub mod mycmd_cmd;` to the ecosystem's `mod.rs`
+   - Ecosystem `mod.rs` files use `automod::dir!()` — any `.rs` file in the directory becomes a public module automatically. No manual `pub mod` needed, but be aware: WIP or helper files will also be exposed. Only commit command-ready modules.
    - Add variant to `Commands` enum in `main.rs` with `#[arg(trailing_var_arg = true, allow_hyphen_values = true)]`
    - Add routing match arm in `main.rs`: `Commands::Mycmd { args } => mycmd_cmd::run(&args, cli.verbose)?,`
 3. **Add rewrite pattern** — Entry in `src/discover/rules.rs` (PATTERNS + RULES arrays at matching index) so hooks auto-rewrite the command

src/cmds/cloud/container.rs

@@ -39,7 +39,10 @@ where
         label,
         |stdout| match serde_json::from_str::<Value>(stdout) {
             Ok(json) => filter_fn(&json),
-            Err(_) => stdout.to_string(),
+            Err(e) => {
+                eprintln!("[rtk] kubectl: JSON parse failed: {}", e);
+                stdout.to_string()
+            }
         },
         RunOptions::stdout_only()
             .early_exit_on_failure()

src/core/runner.rs

@@ -108,10 +108,15 @@ where
         eprintln!("{}", stderr.trim());
     }
 
+    let raw_for_tracking = if opts.filter_stdout_only {
+        stdout.as_ref()
+    } else {
+        raw.as_str()
+    };
     timer.track(
         &format!("{} {}", tool_name, args_display),
         &format!("rtk {} {}", tool_name, args_display),
-        &raw,
+        raw_for_tracking,
         &filtered,
     );