Fix: install maliba-ai lazily at runtime, not at build time

maliba-ai 2.0.0b0 has strict pins (soundfile==0.13.1, librosa==0.11.0)
that conflict with our requirements.txt. Removing it from requirements.txt
and installing it via subprocess on the first Bambara TTS call instead.

This pattern is standard for HF Spaces when a dependency has irreconcilable
version conflicts with the rest of the stack.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

requirements.txt

@@ -21,9 +21,9 @@ huggingface-hub==1.9.0
 peft==0.18.1
 
 # Audio processing
-librosa>=0.10.2
-soundfile>=0.12.1
-audiomentations>=0.43.1
+librosa==0.10.2
+soundfile==0.12.1
+audiomentations==0.43.1
 
 # Quantization (CPU: installs fine; 4-bit/8-bit requires GPU at runtime)
 bitsandbytes==0.49.2
@@ -52,6 +52,5 @@ scipy==1.15.2
 # Phrase matching (fuzzy match for Whisper mis-transcriptions of Bambara/Fula)
 rapidfuzz==3.13.0
 
-# Bambara TTS — MALIBA-AI (non-Meta, Mali community, 10 native speakers)
-# Installed from GitHub; no PyPI release yet.
-maliba-ai @ git+https://github.com/MALIBA-AI/bambara-tts.git
+# maliba-ai is NOT listed here — it has strict conflicting pins (librosa, soundfile).
+# It is installed lazily at runtime on first Bambara TTS call (see src/tts/waxal_tts.py).

src/tts/waxal_tts.py

@@ -82,15 +82,31 @@ class WaxalTTSEngine:
     # ── Bambara (MALIBA-AI) ───────────────────────────────────────────────────
 
     def _load_bambara(self) -> None:
+        # maliba-ai has strict dependency pins that conflict with the main requirements.txt,
+        # so it is NOT listed there. Install it on first use instead.
         try:
             from maliba_ai.tts.inference import BambaraTTSInference
+        except ImportError:
+            logger.info("WaxalTTS: installing maliba-ai (first Bambara TTS call)…")
+            try:
+                import subprocess, sys
+                subprocess.run(
+                    [sys.executable, "-m", "pip", "install", "-q",
+                     "git+https://github.com/MALIBA-AI/bambara-tts.git"],
+                    check=True,
+                    capture_output=True,
+                )
+                from maliba_ai.tts.inference import BambaraTTSInference
+            except Exception as exc:
+                self._bam_error = f"maliba-ai install failed: {exc}"
+                logger.error("WaxalTTS: %s", self._bam_error)
+                return
+
+        try:
             with self._lock:
                 self._bam_tts   = BambaraTTSInference()
                 self._bam_ready = True
             logger.info("WaxalTTS: Bambara TTS ready (MALIBA-AI)")
-        except ImportError:
-            self._bam_error = "maliba-ai package not installed"
-            logger.warning("WaxalTTS: %s", self._bam_error)
         except Exception as exc:
             self._bam_error = str(exc)
             logger.error("WaxalTTS: Bambara load failed: %s", exc)