docs: rename screenshots to descriptive names

Switch the screenshot convention from positional numbers (tls_scr_8) to
self-documenting names (locator, locator_picker, map_target, …). Names say what
they show, so a shot can be re-captured or inserted without renumbering, and a
reference can't silently point at the wrong image. Per-doc directories keep the
names unambiguous, so no prefix is needed (overview_oled.png lives in each
screen's own folder).

git mv on every existing PNG + ref updates across all six solo_features docs;
the pending placeholders adopt the same scheme.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/solo_features/message_screen/message_screen.md

@@ -6,7 +6,7 @@
 
 |           OLED            |           E-Ink           |
 | :-----------------------: | :-----------------------: |
-| ![](./mes_scr_1_oled.png) | ![](./mes_scr_1_eink.png) |
+| ![](./overview_oled.png) | ![](./overview_eink.png) |
 
 The Messages screen is split into three modes — **DMs**, **Channels**, and **Rooms** — selectable with UP/DOWN on the mode-select screen. Each mode shows the corresponding list of conversations with unread counters.
 
@@ -16,7 +16,7 @@ The Messages screen is split into three modes — **DMs**, **Channels**, and **R
 
 |           OLED            |           E-Ink           |
 | :-----------------------: | :-----------------------: |
-| ![](./mes_scr_2_oled.png) | ![](./mes_scr_2_eink.png) |
+| ![](./compose_oled.png) | ![](./compose_eink.png) |
 
 Press **Enter** on a contact or channel to open its history, then press **Enter** again (or select an empty send row) to compose a message. Choose between:
 
@@ -44,7 +44,7 @@ Sensor placeholders appear automatically in the placeholder picker when the corr
 
 |           OLED            |           E-Ink           |
 | :-----------------------: | :-----------------------: |
-| ![](./mes_scr_3_oled.png) | ![](./mes_scr_3_eink.png) |
+| ![](./history_oled.png) | ![](./history_eink.png) |
 
 Each entry in the history list shows the sender name and a compact age indicator (`3m`, `2h`, `>1d`) in the top-right corner.
 
@@ -56,7 +56,7 @@ Each entry in the history list shows the sender name and a compact age indicator
 
 |           OLED            |           E-Ink           |
 | :-----------------------: | :-----------------------: |
-| ![](./mes_scr_4_oled.png) | ![](./mes_scr_4_eink.png) |
+| ![](./fullscreen_oled.png) | ![](./fullscreen_eink.png) |
 
 Navigate between messages with **LEFT** (newer) and **RIGHT** (older). Long messages scroll with **UP/DOWN**.
 
@@ -64,7 +64,7 @@ If the message is a reply addressed to someone (`@[nick]`), a **To: nick** bar i
 
 |           OLED            |           E-Ink           |
 | :-----------------------: | :-----------------------: |
-| ![](./mes_scr_5_oled.png) | ![](./mes_scr_5_eink.png) |
+| ![](./fullscreen_menu_oled.png) | ![](./fullscreen_menu_eink.png) |
 
 **Hold Enter** in fullscreen opens the options menu. It always offers **Reply** for an incoming message, and when the message contains a **location** it adds two more:
 
@@ -81,7 +81,7 @@ A location is any `lat,lon` pair in the text — exactly what the `{loc}` placeh
 
 |           OLED            |           E-Ink           |
 | :-----------------------: | :-----------------------: |
-| ![](./mes_scr_6_oled.png) | ![](./mes_scr_6_eink.png) |
+| ![](./ctx_contact_oled.png) | ![](./ctx_contact_eink.png) |
 
 | Item                         | Action                                                                         |
 | ---------------------------- | ------------------------------------------------------------------------------ |
@@ -98,7 +98,7 @@ When **Pin to dial** is selected, a slot picker opens (Slot 1–6 showing curren
 
 |           OLED            |           E-Ink           |
 | :-----------------------: | :-----------------------: |
-| ![](./mes_scr_7_oled.png) | ![](./mes_scr_7_eink.png) |
+| ![](./ctx_channel_oled.png) | ![](./ctx_channel_eink.png) |
 
 **Hold Enter** on a channel entry opens a context menu: