docs: correct semantically stale content across the user and developer guides

A second-pass content audit checked the guides' substantive claims
against the code (the first pass only fixed mechanical drift). Fixes:

- GETTING_STARTED: described booting a prebuilt SD image and seeing
  default clock/weather plugins — neither exists. Now documents the real
  install (Pi OS Lite + one-shot installer / first_time_install.sh) and
  that displays come from the Plugin Store. Duration and ordering
  instructions moved to the Rotation tab where the controls actually
  live.
- WEB_INTERFACE_GUIDE: three whole tabs were undocumented (Rotation,
  Backup & Restore, Tools) and the Display tab's Vegas Scroll section
  was unmentioned. Fonts overrides are per display element (not per
  plugin); Logs has an Auto-scroll checkbox (not a Pause button); the
  aspirational keyboard-shortcut list and no-JS claim removed.
- TROUBLESHOOTING: the hand-written service-file template (wrong user,
  wrong ExecStart, dropped the autostart gate) replaced with the real
  systemd/ units + install scripts; recovery steps no longer copy
  placeholder units verbatim; WiFi curl endpoint corrected to /api/v3/;
  cache-clearing advice now targets the real cache locations.
- ADVANCED_FEATURES: removed a false claim that CacheManager has no
  delete(); fixed two example snippets that raise TypeError
  (BackgroundDataService and get_config_file_mode signatures); fixed
  cache paths, a 5-minute TTL that is actually 1 hour, and the vegas
  table now links the complete 26-key reference.
- EMULATOR_SETUP_GUIDE: documented run.py flags that don't exist
  (--plugin/--test-plugins) removed in favor of dev_server.py and
  check_plugin.py; shipped emulator config values corrected (browser
  adapter default on :8888, not pygame).
- PLUGIN_QUICK_REFERENCE: drag-and-drop reordering is shipped, not
  'not yet supported'; discovery-fallback and registry-repo claims
  corrected. PLUGIN_API_REFERENCE: get_vegas_segment_width returns
  panels, not pixels. CONTRIBUTING: the repo uses flake8/mypy/bandit
  pre-commit hooks, not black/ruff, and tests need requirements-test.txt.
- SKIN_SYSTEM/DEVELOPER_QUICK_REFERENCE: stale module paths.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SXb4mKcAkVaxkeTb3YnAdr

docs/GETTING_STARTED.md

@@ -21,18 +21,30 @@ This guide will help you set up your LEDMatrix display for the first time and ge
 
 ---
 
-## Quick Start (5 Minutes)
+## Quick Start
 
-### 1. First Boot
+### 1. Install LEDMatrix
 
-1. Insert the MicroSD card with LEDMatrix installed
-2. Connect the LED matrix to your Raspberry Pi
-3. Plug in the power supply
-4. Wait for the Pi to boot (about 60 seconds)
+There is no prebuilt SD card image — you install LEDMatrix onto stock
+Raspberry Pi OS Lite yourself:
 
-**Expected Behavior:**
+1. Flash Raspberry Pi OS Lite to the MicroSD card (Raspberry Pi Imager)
+2. Connect the LED matrix to your Raspberry Pi, insert the card, and
+   power on
+3. SSH into the Pi and run the one-shot installer:
+   ```bash
+   curl -fsSL https://raw.githubusercontent.com/ChuckBuilds/LEDMatrix/main/scripts/install/one-shot-install.sh | bash
+   ```
+   or clone the repo and run `sudo ./first_time_install.sh` — see the
+   [README Installation Steps / Quick Install](../README.md#installation-steps)
+   for full details
+
+**Expected Behavior after install:**
 - LED matrix will light up
-- Display will show default plugins (clock, weather, etc.)
+- A fresh install ships only the bundled `starlark-apps` and
+  `web-ui-info` plugins — clock, weather, sports, etc. must be
+  installed from the Plugin Store (web UI → Plugin Manager) before
+  anything else displays
 - Pi creates WiFi network "LEDMatrix-Setup" if not connected
 
 ### 2. Connect to WiFi
@@ -73,7 +85,7 @@ You should see:
 2. Set your matrix configuration:
    - **Rows**: 32 or 64 (match your hardware)
    - **Columns**: commonly 64 or 96; the web UI accepts any integer
-     in the 16–128 range, but 64 and 96 are the values the bundled
+     in the 1–128 range, but 64 and 96 are the values the bundled
      panel hardware ships with
    - **Chain Length**: Number of panels chained horizontally
    - **Hardware Mapping**: usually `adafruit-hat-pwm` (with the PWM jumper
@@ -115,11 +127,16 @@ You can also install community plugins straight from a GitHub URL using the
 
 1. Each installed plugin gets its own tab in the second navigation row
 2. Open that plugin's tab to edit its settings (favorite teams, API keys,
-   update intervals, display duration, etc.)
+   update intervals, etc.)
 3. Click **Save**
 4. Restart the display service from **Overview** so the new settings take
    effect
 
+**Note:** how long each plugin stays on screen is not set in the
+plugin's own tab — use the **Rotation** tab's **Screen Durations**
+section instead (saved to `display.display_durations` in
+`config.json`).
+
 **Example: Weather Plugin**
 - Set your location (city, state, country)
 - Add an API key from OpenWeatherMap (free signup) to
@@ -208,12 +225,14 @@ The fastest way to verify a plugin works without waiting for the rotation:
 ### Customize Your Display
 
 **Adjust display durations:**
-- Each plugin's tab has a **Display Duration (seconds)** field — set how
-  long that plugin stays on screen each rotation.
+- Open the **Rotation** tab and use the **Screen Durations** section to
+  set how long each plugin stays on screen per rotation (saved to
+  `display.display_durations`).
 
 **Organize plugin order:**
-- Use the **Plugin Manager** tab to enable/disable plugins. The display
-  cycles through enabled plugins in the order they appear.
+- The **Rotation** tab also has a drag-and-drop **Rotation Order** list
+  (saved to `display.plugin_rotation_order`). Enable/disable plugins
+  from the **Plugin Manager** tab.
 
 **Add more plugins:**
 - Check the **Plugin Store** section of **Plugin Manager** for new plugins.
@@ -280,10 +299,14 @@ sudo journalctl -u ledmatrix-web -f
 │   ├── config_secrets.json   # API keys and secrets
 │   └── wifi_config.json      # WiFi settings
 ├── plugin-repos/             # Installed plugins (default location)
-├── cache/                    # Cached data
 └── web_interface/            # Web interface files
 ```
 
+> Cached data does not live in the project directory — the cache manager
+> uses the first writable location among `/var/cache/ledmatrix`,
+> `~/.ledmatrix_cache`, `/opt/ledmatrix/cache`, and
+> `$TMPDIR/ledmatrix_cache`.
+
 > The plugin install location is configurable via
 > `plugin_system.plugins_directory` in `config.json`. The default is
 > `plugin-repos/`. Plugin discovery (`PluginManager.discover_plugins()`)
@@ -303,11 +326,14 @@ System tabs:
 - WiFi              Network selection and AP-mode setup
 - Schedule          Power and dim schedules
 - Display           Matrix hardware configuration
+- Rotation          Rotation order (drag-and-drop) and screen durations
 - Config Editor     Raw config.json editor
+- Backup & Restore  Config backup and restore
 - Fonts             Upload and manage fonts
 - Logs              Real-time log viewing
 - Cache             Cached data inspection and cleanup
 - Operation History Recent service operations
+- Tools             System diagnostics, updates, dependencies, maintenance
 
 Plugin tabs (second row):
 - Plugin Manager    Browse the Plugin Store, install/enable plugins