feat(cli): support relative minutes in radio schedules

docs/cli_commands.md

@@ -1285,11 +1285,17 @@ intervals and the 24-hour watchdog policy. An explicitly saved normal-mode
 - `bw`: Bandwidth in kHz (same allowed values as `set radio`)
 - `sf`: Spreading factor (5-12)
 - `cr`: Coding rate (5-8)
-- `start_time`: Unix epoch time when the setting starts
-- `end_time`: Unix epoch time when a temporary setting reverts
+- `start_time`: UTC Unix epoch seconds, or `+N` for N whole minutes from now
+- `end_time`: UTC Unix epoch seconds, or `+N` for N whole minutes from now
 - `n`: Scheduled entry number from `get radioat` or `get tempradioat`
 
 **Notes:**
+- Both relative endpoints use the same command-time snapshot of the node clock.
+  For example, `set tempradioat 910.5,500,8,5,+5,+15` starts in 5 minutes
+  and reverts in 15 minutes (10 minutes active). `set radioat 910.5,500,8,5,+5`
+  schedules a saved change in 5 minutes. Bare numbers remain absolute timestamps;
+  absolute and relative endpoints can be mixed. Relative offsets must be positive.
+  The existing scheduler and clock behavior are unchanged.
 - `get radioat` and `get tempradioat` list all entries when `n` is omitted.
 - `del radioat` and `del tempradioat` delete all entries when `n` is omitted.
 - Each queue supports 3 entries. Scheduled entries are not saved across reboot.

docs/radio_profiles.md

@@ -427,7 +427,7 @@ See the [implementation and validation notes](radio_dwell_policy_validation.md).
 
 ## Schedule the second profile
 
-Use UTC Unix timestamps (seconds):
+Use UTC Unix timestamps (seconds), or `+N` for N whole minutes from now:
 
 ```text
 set radioat2 910.5,500,8,5,rxtx,START[,PREAMBLE]
@@ -440,12 +440,20 @@ del radioat2 1
 del tempradioat2 all
 ```
 
-Replace `START`, `END` and the optional `PREAMBLE` with numbers; omit the square
+Replace `START` and `END` with timestamps or `+N`, and the optional `PREAMBLE`
+with a number; omit the square
 brackets. Each schedule family has four slots. Times must be in the future and
 within 24 days. Overlapping temporary second-profile sessions are rejected.
 `radioat2` changes the saved second profile when it starts; `tempradioat2`
 restores the saved profile at its end. Pending schedules do not survive reboot.
 
+For example, `set tempradioat2 910.5,500,8,5,rxtx,+5,+15` starts in 5 minutes
+and restores in 15 minutes (10 minutes active). Both offsets are measured from
+the same node-clock snapshot when accepting the command, not from each other.
+`set radioat2 910.5,500,8,5,rxtx,+5` schedules a saved change in 5 minutes.
+Offsets must be positive whole minutes. Absolute and relative endpoints can be
+mixed; bare numbers still mean UTC seconds. Existing clock requirements apply.
+
 ## Return to one profile
 
 ```text