redbear-power: organize help text with section dividers, fix theme list

Help now uses ──────── SECTION ──────── dividers for Power & CPU,
Process Management, and Navigation. TOML config theme.mode lists
all 6 themes (nord, gruvbox, solarized-dark were missing).

local/recipes/system/redbear-power/source/src/render.rs

@@ -2120,7 +2120,8 @@ TOML CONFIG:
         dbus_name             string (default \"org.redbear.Power\")
 
       [theme]
-        mode                  \"dark\" | \"light\" | \"high-contrast\"
+        mode                  \"dark\" | \"light\" | \"high-contrast\" | \"nord\"
+                              | \"gruvbox\" | \"solarized-dark\"
         focused_border        Color name (e.g. \"yellow\", \"white\", \"cyan\")
         dim_border            Color name
 
@@ -2139,12 +2140,14 @@ TOML CONFIG:
 
 INTERACTIVE CONTROLS:
 
-TABS:
+──────── TABS ────────
     [1] Per-CPU         [2] System         [3] Info
     [4] Motherboard     [5] Battery        [6] Sensors
     [7] Network         [8] Storage        [9] Process
     [T] cycle to next tab
 
+──────── POWER & CPU ────────
+
     [g]    cycle governor (Performance / Ondemand / Powersave)
     [p/P]  step selected CPU P-state down / up
     [m/M]  force selected CPU to min / max P-state
@@ -2166,6 +2169,9 @@ TABS:
     [Enter] toggle P-state expansion for selected CPU
     [e]    expand current tab to full-screen (toggle)
     [f]    freeze / unfreeze data updates
+
+──────── PROCESS MANAGEMENT ────────
+
     [k]    kill selected process (Process tab only)
     [N]    edit nice value of selected process (Process tab)
     [l]    list open file descriptors of selected process (Process tab)
@@ -2175,6 +2181,9 @@ TABS:
     [o]    cycle process sort mode
     [i]    invert sort direction
     [Space] fold/unfold process subtree (tree mode)
+
+──────── NAVIGATION ────────
+
     [Home] jump to top of list
     [End]  jump to bottom of list
     [G]    jump to bottom (vim-style)
@@ -2189,7 +2198,7 @@ MOUSE:
     Middle   toggle P-state expansion (table), toggle throttle (controls)
     [q]      quit
 
-NOTES:
+──────── NOTES ────────
     - MSR writes (g, p, P, m, M, t) require CAP_SYS_MSR; the binary is
       intended to run as root (euid 0).
     - When MSR or cpufreq schemes are absent (e.g., QEMU without MSR),