chore(diag): log internal DRAM next to PSRAM-dominated heap totals

"free heap 5.8MB" in the crash log was PSRAM and masked the actual
internal-RAM exhaustion. git_sync's publish/commit/push lines now
carry the MALLOC_CAP_INTERNAL reading, and boot brackets the palette
file-list build with it — small Strings are forced internal by the
16 KB SPIRAM malloc threshold, so the 1098-path list is a suspected
~60-70 KB DRAM consumer competing with Wi-Fi/TLS; the log decides
whether interning into one PSRAM buffer is worth it.

firmware/src/git_sync.rs

@@ -248,9 +248,10 @@ fn publish_cycle(
 /// error, surfaced as such.
 fn publish_once(paths: &BTreeSet<String>) -> Result<PublishOutcome> {
     log::info!(
-        "publish started — {} dirty path(s), free heap {}",
+        "publish started — {} dirty path(s), free heap {} ({} internal)",
         paths.len(),
-        free_heap()
+        free_heap(),
+        internal_free_heap()
     );
     let repo = Repository::open(REPO_DIR).with_context(|| {
         format!("opening git repo at {REPO_DIR} — provision the card with a clone (just init) whose origin is your remote")
@@ -313,8 +314,9 @@ fn publish_once(paths: &BTreeSet<String>) -> Result<PublishOutcome> {
     }
 
     log::info!(
-        "push done — free heap {}, min-ever {}",
+        "push done — free heap {} ({} internal), min-ever {}",
         free_heap(),
+        internal_free_heap(),
         min_free_heap()
     );
     Ok(PublishOutcome::Pushed(short(oid)))
@@ -388,11 +390,12 @@ fn stage_and_commit(repo: &Repository, paths: &BTreeSet<String>) -> Result<Optio
         .commit(Some("HEAD"), &sig, &sig, &message, &tree, &parents)
         .context("creating commit")?;
     log::info!(
-        "commit split — splice {splice_ms}ms ({} path(s)), commit-obj {}ms; committed {} — free heap {}",
+        "commit split — splice {splice_ms}ms ({} path(s)), commit-obj {}ms; committed {} — free heap {} ({} internal)",
         paths.len(),
         t_commit.elapsed().as_millis(),
         short(oid),
-        free_heap()
+        free_heap(),
+        internal_free_heap()
     );
     Ok(Some(oid))
 }
@@ -636,6 +639,14 @@ fn free_heap() -> u32 {
     unsafe { sys::esp_get_free_heap_size() }
 }
 
+/// Free INTERNAL RAM (DRAM), excluding PSRAM. `free_heap` is dominated by the
+/// 8 MB PSRAM pool and masks internal exhaustion — which is what actually
+/// killed the first real-repo push (mbedTLS's ssl_setup could not get its
+/// ~33 KB while Wi-Fi + USB + editor + libgit2 were resident).
+fn internal_free_heap() -> u32 {
+    unsafe { sys::heap_caps_get_free_size(sys::MALLOC_CAP_INTERNAL) as u32 }
+}
+
 fn min_free_heap() -> u32 {
     unsafe { sys::esp_get_minimum_free_heap_size() }
 }

firmware/src/main.rs

@@ -123,7 +123,18 @@ fn main() -> anyhow::Result<()> {
     ed.set_notice(format!("loaded {name}"));
     // Feed the file palette (Ctrl-P). Enumerated once at boot — the v0.5 slices
     // that create/delete files (`:enew`, delete) will re-feed it then.
+    // Bracketed with internal-DRAM readings: each path is a small String, kept
+    // internal by the SPIRAM malloc threshold (16 KB), so the list competes
+    // with Wi-Fi/TLS for DRAM. Estimate to confirm: ~60-70 KB at 1098 files —
+    // this number decides whether interning the paths into one shared buffer
+    // (a single >16 KB alloc, which lands in PSRAM) is worth the refactor.
+    let dram_before = internal_free_heap();
     ed.set_file_list(enumerate_files());
+    let dram_after = internal_free_heap();
+    log::info!(
+        "file list: internal heap {dram_before} -> {dram_after} ({} KB consumed)",
+        dram_before.saturating_sub(dram_after) / 1024
+    );
     // Editor preferences (.typoena.toml, git-tracked). Read before the first
     // render so `line_numbers` shapes the opening frame. A missing / unreadable /
     // partial file falls back to defaults, so a fresh card just works.
@@ -611,6 +622,13 @@ fn walk_files(dir: &std::path::Path, depth: usize, out: &mut Vec<String>) {
     }
 }
 
+/// Free internal DRAM (excludes the 8 MB PSRAM pool, which dominates the total
+/// free-heap number and masks DRAM exhaustion). Same reading `git_sync` logs.
+fn internal_free_heap() -> u32 {
+    use esp_idf_svc::sys;
+    unsafe { sys::heap_caps_get_free_size(sys::MALLOC_CAP_INTERNAL) as u32 }
+}
+
 /// A file's display name — its basename without extension (`/sd/repo/notes.md`
 /// → `notes`), for the snackbar. Falls back to the raw path if it has no stem.
 fn file_stem(path: &str) -> &str {