refactor: rename firmware from Plus to Solo

- FIRMWARE_VERSION: v1.15-plus.1 → v1.15-solo.1
- FIRMWARE_PLUS_BUILD → FIRMWARE_SOLO_BUILD in all platformio.ini and UITask.cpp
- docs/plus_features/ → docs/solo_features/ (all sub-docs moved)
- README: update all doc links plus new Documentation section
- GitHub Actions: extract GIT_TAG_VERSION in each build job (was missing,
  causing empty FIRMWARE_VERSION in builds); rename output files to
  solo-VERSION-oled.uf2 / solo-VERSION-eink.uf2; release title → "Solo VERSION"

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/solo_features/tools_screen/tools_screen.md

@@ -0,0 +1,173 @@
+## Tools Screen
+
+[Go back](../../../README.md)
+
+### Overview
+
+|           OLED            |           E-Ink           |
+| :-----------------------: | :-----------------------: |
+| ![](./tls_scr_1_oled.png) | ![](./tls_scr_1_eink.png) |
+
+The Tools screen is a hub for GPS trail recording, nearby node browsing, ringtone editing, auto-reply bot, and auto-advert. Navigate the tool list with **UP/DOWN** and press **Enter** to open a tool.
+
+---
+
+## Nearby Nodes
+
+|           OLED            |           E-Ink           |
+| :-----------------------: | :-----------------------: |
+| ![](./tls_scr_2_oled.png) | ![](./tls_scr_2_eink.png) |
+
+Browse nodes that have recently advertised on the mesh. Filter by category with **LEFT/RIGHT**:
+
+| Filter | Shows                          |
+| ------ | ------------------------------ |
+| Fav    | Upstream-starred contacts only |
+| ALL    | All known nodes                |
+| Comp   | Companion (chat) nodes         |
+| Rpt    | Repeaters                      |
+| Room   | Room servers                   |
+| Snsr   | Sensors                        |
+
+Select a node to see its coordinates, distance, bearing with cardinal direction, type, and last-heard time.
+
+**Hold Enter** → context menu → **Discover nearby** to send a live `NODE_DISCOVER_REQ` ping.
+
+> [!TIP]
+> Combined with **Auto-Advert** on the other device, Nearby Nodes becomes a passive location tracker — as long as the tracked device periodically broadcasts its GPS position, you can see its current distance and bearing without any manual interaction on either end.
+
+---
+
+### Active Discovery
+
+|           OLED            |           E-Ink           |
+| :-----------------------: | :-----------------------: |
+| ![](./tls_scr_3_oled.png) | ![](./tls_scr_3_eink.png) |
+
+Sends a `NODE_DISCOVER_REQ` ping. Repeaters, sensors and room servers within zero-hop range respond immediately with name, type and signal data.
+
+Results show as 2-line cards: node name + type, then RSSI / SNR / remote SNR.
+
+- **UP/DOWN** — navigate results
+- **Enter** — open full-screen detail (public key, signal data, contact status)
+- **Hold Enter** — rescan
+- **Cancel / Back** — return to nearby list
+
+---
+
+## GPS Trail
+
+|           OLED            |           E-Ink           |
+| :-----------------------: | :-----------------------: |
+| ![](./tls_scr_4_oled.png) | ![](./tls_scr_4_eink.png) |
+
+Records your route in a RAM ring buffer (up to 512 points, sampled every 1 s). Tracking runs in the background — a blinking **G** appears in the status bar. The trail survives display auto-off but is lost on reboot unless saved to flash first.
+
+Cycle views with **LEFT / RIGHT**:
+
+| View        | Content                                                                                                                                                             |
+| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| **Summary** | Distance, elapsed time, avg speed or pace, point count, tracking status                                                                                             |
+| **Map**     | Auto-fit dot-and-line plot with cos(lat) aspect correction; segment breaks marked; north arrow; scale grid (toggle with **LEFT/RIGHT** on the Grid row in the menu) |
+| **List**    | Per-point rows showing local time (HH:MM) and delta distance from the previous point; segment-start rows show `start`; scroll with **UP/DOWN**                      |
+
+|           OLED            |           E-Ink           |
+| :-----------------------: | :-----------------------: |
+| ![](./tls_scr_5_oled.png) | ![](./tls_scr_5_eink.png) |
+
+**Hold Enter** opens the action menu:
+
+| Item                  | Interaction         | Action                                              |
+| --------------------- | ------------------- | --------------------------------------------------- |
+| Min dist              | LEFT/RIGHT          | Filter gate: 5 m / 10 m / 25 m / 100 m              |
+| Units                 | LEFT/RIGHT          | Speed/pace: km/h / mph / min/km / min/mi            |
+| Grid                  | LEFT/RIGHT or Enter | Toggle scale grid on the map                        |
+| Start / Stop tracking | Enter               | Begin or end a recording session                    |
+| Save trail            | Enter               | Write RAM ring to flash (`/trail`)                  |
+| Load trail            | Enter               | Restore flash trail into RAM                        |
+| Export (live)         | Enter               | Stream live RAM trail as GPX 1.1 over USB Serial    |
+| Export (saved)        | Enter               | Stream saved flash trail as GPX 1.1 over USB Serial |
+| Reset trail           | Enter               | Clear RAM ring and elapsed time                     |
+
+### Downloading GPX
+
+1. Connect the device via USB cable
+2. Open a serial terminal at **115200 baud**:
+   - **macOS/Linux** — `cat /dev/tty.usbmodem* > track.gpx` (stop with Ctrl-C after dump completes)
+   - **Windows** — PuTTY (Serial, 115200) or Arduino IDE Serial Monitor (no line ending)
+3. On the device: **Tools › Trail** → **Hold Enter** → **Export (live)** or **Export (saved)**
+4. The device streams a GPX 1.1 XML document. Save the output from `<?xml` to `</gpx>` as a `.gpx` file
+5. Import into OsmAnd, Garmin BaseCamp, GPX Studio, Google Earth, etc.
+
+> [!NOTE]
+> If the companion app is connected via **BLE**, the export is safe — BLE and USB operate independently. If connected via **USB**, disconnect the app before exporting.
+
+---
+
+## Auto-Advert
+
+Periodically broadcasts a 0-hop advert with your GPS position. Configurable interval: off / 30 s / 1 min / 2 min / 5 min / 10 min / 30 min / 1 h. A blinking **A** appears in the status bar while active.
+
+---
+
+## Ringtone Editor
+
+|           OLED            |           E-Ink           |
+| :-----------------------: | :-----------------------: |
+| ![](./tls_scr_6_oled.png) | ![](./tls_scr_6_eink.png) |
+
+A step sequencer for composing custom notification melodies. Two slots — **Melody 1** and **Melody 2** — switchable from within the editor.
+
+Each melody supports up to 32 notes:
+
+| Parameter | Options                           |
+| --------- | --------------------------------- |
+| Pitch     | C / D / E / F / G / A / B / pause |
+| Octave    | 4 – 7                             |
+| Duration  | 1/4 / 1/8 / 1/16 / 1/32           |
+| BPM       | 60 / 90 / 120 / 150 / 180         |
+
+**Navigation in the editor:**
+
+- **LEFT/RIGHT** — move between notes
+- **UP/DOWN** — change pitch of selected note
+- **Enter** — cycle octave of selected note
+- **Hold Enter** (or context menu) — open options menu
+
+**Options menu:**
+
+| Item         | Interaction | Action                                 |
+| ------------ | ----------- | -------------------------------------- |
+| Play / Stop  | Enter       | Preview the melody                     |
+| Melody 1 / 2 | Enter       | Switch to the other slot               |
+| Duration     | LEFT/RIGHT  | Cycle duration for selected note       |
+| BPM          | LEFT/RIGHT  | Cycle tempo                            |
+| Insert       | Enter       | Insert a new note after the cursor     |
+| Delete       | Enter       | Delete the note at cursor              |
+| Save & Exit  | Enter       | Persist the melody and return to Tools |
+| Discard      | Enter       | Return to Tools without saving         |
+
+Melodies can be assigned in **Settings › Sound** (global default) or overridden per contact or channel from the Messages screen context menu.
+
+---
+
+## Auto-Reply Bot
+
+|           OLED            |           E-Ink           |
+| :-----------------------: | :-----------------------: |
+| ![](./tls_scr_7_oled.png) | ![](./tls_scr_7_eink.png) |
+
+Automatically replies to incoming messages that contain a configured trigger word (case-insensitive, contains match).
+
+When the bot is enabled it listens to DMs by default. Channel monitoring is an optional addition — select a channel separately to activate it alongside DM mode.
+
+| Setting       | Description                                                                      |
+| ------------- | -------------------------------------------------------------------------------- |
+| Bot           | ON / OFF — enables DM listening                                                  |
+| Channel mode  | ON / OFF — additionally monitors a selected channel                              |
+| Channel       | Which channel to monitor (only relevant when channel mode is ON)                 |
+| Trigger       | Word or phrase that activates the reply (shared by both modes, case-insensitive) |
+| DM reply      | Reply text for DMs; supports `{time}` and `{loc}` placeholders                   |
+| Channel reply | Reply text for channel messages; supports `{time}` and `{loc}` placeholders      |
+
+A 10-second cooldown prevents repeated replies in quick succession.