docs(troubleshooting): lead with the diagnostic step, not a settings tour

The plugin now links here from a button in its Troubleshooting settings tab
(s2b-dev/smart-second-brain#458), so a reader arriving on this page is already
looking at that tab. "Start here" then opened by telling them where to find two
controls sitting on screen behind the page they had just opened, and the closing
section repeated the directions a second time.

Reframe the opening around the one thing worth doing before reading further —
turn on logging and reproduce — and mention the other controls as things that
exist rather than as a place to navigate to. The closing section now assumes
that logging is already on and asks for its output in the issue, instead of
restating where the buttons live.

Also fix the intro's count: it promised "four buckets" and then ran six symptom
sections, since MCP and Mobile are not covered by the four named causes. The
page is organised by symptom, not by cause, so say that instead of counting.

Author: Leo310

src/content/docs/help/troubleshooting.md

@@ -5,21 +5,28 @@ sidebar:
   order: 1
 ---
 
-Most problems fall into one of four buckets: the provider can't be reached, the
-index isn't what you think it is, the agent lacks a tool, or a note is being
-filtered for privacy. This page walks each one.
+Most problems come down to one of a few causes: the provider can't be reached,
+the index isn't what you think it is, the agent lacks a tool, or a note is being
+filtered for privacy. The sections below are organised by what you're seeing
+rather than by cause, so start from the symptom.
 
-## Start here
+## Before you start: turn on logging
 
-**Settings → Smart Second Brain → Troubleshooting** has two things worth
-knowing about:
+Almost every diagnosis below reads better with verbose output. Turn on
+**Developer Console logging** in the plugin's Troubleshooting settings,
+reproduce the problem, and open the developer console (`Ctrl`/`Cmd` + `Shift` +
+`I`) to read the `[S2B]` lines.
 
-- **Developer Console logging.** Turn this on to get verbose `[S2B]` output in
-  the developer console (`Ctrl`/`Cmd` + `Shift` + `I`). Almost every diagnosis
-  below starts here.
-- **Clean up plugin data.** Deletes plugin settings and generated index data.
+Two other things live on that same settings tab, worth knowing before you need
+them:
+
+- **Clean up plugin data** deletes plugin settings and generated index data.
   Your secrets, skill files, and chat files inside the vault are **kept**. This
   is the "start clean without losing my work" button.
+- **View existing issues** and **Open new issue** go straight to the tracker,
+  for when nothing on this page fits.
+
+Then jump to whichever section matches your symptom.
 
 ## The agent won't respond
 
@@ -190,11 +197,8 @@ phone. Consider indexing on desktop against a synced vault.
 
 ## Nothing above helped
 
-Turn on **Developer Console logging**, reproduce the problem, and check the
-console for `[S2B]` lines.
-
-Then search the
+Search the
 [existing issues](https://github.com/s2b-dev/smart-second-brain/issues) before
 opening a new one. If you do open one, include what you tried, any error
-messages, and the steps to reproduce. Both buttons are in the Troubleshooting
-settings tab.
+messages, the steps to reproduce, and the `[S2B]` console output from the
+logging you turned on at the top of this page.