feat(l1): Save per channel, and Keep messages Off deletes the log at the next start

Channel options > Save keeps a busy channel's new messages off the flash, so
it leaves the room to the others; Keep messages stays the master switch.
Off now only stops the saving, so a value stepped past costs nothing and the
wait for the delete comes at a start. Delete history stays immediate.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/companion_radio/ui-core/ChannelControl.h

@@ -259,6 +259,13 @@ static void setFavourite(NodePrefs* p, uint8_t idx, bool on) {
   if (on) p->ch_fav_bitmask |= 1ULL << idx; else p->ch_fav_bitmask &= ~(1ULL << idx);
 }
 
+// Whether new messages of this channel go to the flash log (HistoryLog.h).
+static bool saved(const NodePrefs* p, uint8_t idx) { return !p || !(p->ch_no_save & (1ULL << idx)); }
+static void setSaved(NodePrefs* p, uint8_t idx, bool on) {
+  if (!p) return;
+  if (on) p->ch_no_save &= ~(1ULL << idx); else p->ch_no_save |= 1ULL << idx;
+}
+
 // Scope as a picker row: 0 = Default (follow the list's default), then the
 // list itself from 1 ("*" = unscoped, then the named entries).
 static uint8_t scope(const NodePrefs* p, uint8_t idx) {
@@ -274,8 +281,8 @@ static uint8_t scopeFromRow(int row) {
 // here, so a channel re-added at a freed slot can't inherit the old one's
 // settings. Adding such a field: clear it below (and mark it in NodePrefs.h).
 // Covers bot_channel_idx, loc_share_channel_idx, ch_notif_melody_*,
-// ch_notif_override / ch_notif_muted, ch_fav_bitmask, favourite dial slots,
-// ch_scope_idx. True when something changed (caller saves).
+// ch_notif_override / ch_notif_muted, ch_fav_bitmask, ch_no_save, favourite dial
+// slots, ch_scope_idx. True when something changed (caller saves).
 static bool onRemoved(NodePrefs* p, uint8_t idx) {
   if (!p) return false;
   bool changed = false;
@@ -286,6 +293,7 @@ static bool onRemoved(NodePrefs* p, uint8_t idx) {
   if (p->ch_notif_melody_set & m) { p->ch_notif_melody_set &= ~m; p->ch_notif_melody_2 &= ~m; changed = true; }
   if (p->ch_notif_override & m)   { p->ch_notif_override &= ~m; p->ch_notif_muted &= ~m; changed = true; }
   if (p->ch_fav_bitmask & m)      { p->ch_fav_bitmask &= ~m; changed = true; }
+  if (p->ch_no_save & m)          { p->ch_no_save &= ~m; changed = true; }
   if (idx < NodePrefs::MAX_SCOPED_CHANNELS && p->ch_scope_idx[idx] != NodePrefs::CH_SCOPE_DEFAULT) {
     p->ch_scope_idx[idx] = NodePrefs::CH_SCOPE_DEFAULT;   // back to Default, as a new channel
     changed = true;

examples/companion_radio/ui-core/HistoryLog.h

@@ -25,7 +25,9 @@
 // A record: Rec, the path, the text, then its own total length as one byte, so
 // the log can be walked from the end. restore() fills the RAM rings from there.
 // A channel's messages carry channelKey(), so they follow the channel, not the
-// slot; those of a channel since deleted aren't restored.
+// slot; those of a channel since deleted aren't restored. A channel with Save
+// off (chanctl::saved()) stays out of the log from then on; what it has there
+// stays until it ages out.
 //
 // Older messages, past what the rings hold, are read a page at a time
 // (pageBegin*(), pageOlder(), pageNewer()): the messages screen measures its
@@ -54,6 +56,8 @@ public:
     if (_on) {
       scan();
       restore();
+    } else if (_fs && _fs->exists(ROOT)) {
+      forget();   // Keep messages off since the last start, see loop()
     }
     _next_prune = millis() + SAVE_DELAY_MS;
     history->setArchive(this);
@@ -61,8 +65,12 @@ public:
 
   // ── HistArchive ────────────────────────────────────────────────────────────
   // arc_id orders the entries of this run; a restored one keeps 0, already saved.
-  void chAppend(ChHistEntry& e) override { e.arc_id = ++_seq; appended(); }
-  void chUpdate(const ChHistEntry&) override { touch(); }
+  void chAppend(ChHistEntry& e) override {
+    if (!chanctl::saved(_prefs, e.ch_idx)) { e.arc_id = NOT_SAVED; return; }
+    e.arc_id = ++_seq;
+    appended();
+  }
+  void chUpdate(const ChHistEntry& e) override { if (e.arc_id != NOT_SAVED) touch(); }
   void dmAppend(DmHistEntry& e) override { e.arc_id = ++_seq; appended(); }
   void dmUpdate(const DmHistEntry&) override { touch(); }
 
@@ -70,7 +78,9 @@ public:
     bool on = _fs && _prefs && _prefs->msg_keep;
     if (on != _on) {
       _on = on;
-      if (on) touch(); else forget();
+      // Off only stops the saving; begin() deletes the log, so a value stepped
+      // past on the way to another costs nothing, and the wait comes at a start.
+      if (on) touch(); else _dirty = false;
     }
     if (_dirty && (int32_t)(millis() - _due) >= 0) flush(false);
     if (_on && (int32_t)(millis() - _next_prune) >= 0) {
@@ -177,6 +187,9 @@ public:
 
 private:
   static constexpr const char* ROOT = "/h";
+  // arc_id of a message that stays in the ring: a channel with Save off. Above
+  // any _ch_done, so it never counts as in the log (pageBeginCh).
+  static const uint32_t NOT_SAVED = 0xFFFFFFFFUL;
 
   struct __attribute__((packed)) Rec {
     uint32_t key;         // channelKey(), or a DM's 4-byte public key prefix
@@ -250,7 +263,7 @@ private:
     uint32_t now = rtc_clock.getCurrentTime();
     for (int j = _history->chHistCount() - 1; j >= 0; j--) {
       const ChHistEntry& e = _history->chAtPos(_history->chHistPosNewest(j));
-      if (e.arc_id <= _ch_done) continue;
+      if (e.arc_id <= _ch_done || e.arc_id == NOT_SAVED) continue;
       if (!all && e.relay_status == ACK_PENDING && now - e.timestamp < SETTLE_SECS) { more = true; break; }
       ChannelDetails ch;
       if (the_mesh.getChannel(e.ch_idx, ch) && ch.name[0] &&

examples/companion_radio/ui-core/UiCore.h

@@ -15,6 +15,7 @@
 
 #include "MessageHistory.h"
 #ifdef HIST_FLASH
+#include "ChannelControl.h"   // chanctl::saved()
 #include "HistoryLog.h"
 #endif
 #include "DmUnreadTable.h"