feat: integrate tracing and enhance bit matrix operations

Add the `tracing` crate to `obidebruinj`, `obisys`, and resolve it in `Cargo.lock`. Replace `eprintln!` statements with structured `debug!` and `info!` macros. Introduce a `TracedBar` wrapper for progress bars and enhance the `Stage` lifecycle to emit structured events for timing, memory metrics, and swap warnings. Add a progress spinner for unitig degree computation. Extend `PersistentBitMatrix` with columnar bit-vector operations and parallel distance methods, enabling uniform distance computations across all storage layouts while replacing previous panics with dimension-based fallbacks.

src/obidebruinj/Cargo.toml

@@ -10,6 +10,7 @@ ahash = "0.8"
 hashbrown = { version = "0.14", features = ["rayon"] }
 rayon     = "1"
 xxhash-rust = { version = "0.8.15", features = ["xxh3", "const_xxh3"] }
+tracing    = "0.1"
 
 [features]
 test-utils = []

src/obidebruinj/src/debruijn.rs

@@ -2,10 +2,11 @@
 use hashbrown::HashMap;
 use obikseq::k;
 use obikseq::{CanonicalKmer, Sequence};
-use rayon::prelude::*;
+use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
 use std::fmt;
 use std::sync::atomic::{AtomicU8, Ordering};
 use xxhash_rust::xxh3::Xxh3Builder;
+use tracing::{debug, info};
 
 // ── Types ─────────────────────────────────────────────────────────────────────
 
@@ -379,7 +380,7 @@ impl GraphDeBruijn {
             });
 
             let n = n_new.load(Ordering::Relaxed);
-            eprintln!("[for_each_unitig] pass {}: {} starts", pass, n);
+            debug!("[for_each_unitig] pass {}: {} starts", pass, n);
             n_chains.fetch_add(n, Ordering::Relaxed);
             pass += 1;
             if n == 0 {
@@ -410,11 +411,11 @@ impl GraphDeBruijn {
             }
         }
 
-        eprintln!(
-            "[for_each_unitig] chains={} phase2={} total={}",
-            n_chains.load(Ordering::Relaxed),
-            n2.load(Ordering::Relaxed),
-            n_chains.load(Ordering::Relaxed) + n2.load(Ordering::Relaxed),
+        info!(
+            chains = n_chains.load(Ordering::Relaxed),
+            phase2 = n2.load(Ordering::Relaxed),
+            total  = n_chains.load(Ordering::Relaxed) + n2.load(Ordering::Relaxed),
+            "unitig traversal complete"
         );
     }