refactor: split glm.c into colibri.c + 4 header modules

Rename glm.c → colibri.c and extract four self-contained modules
into header-only files (same pattern as st.h/tier.h/grammar.h):

  quant.h      (672 lines) — SIMD matmul kernels, quantization
  sample.h     (143 lines) — RNG, top-p sampling, stop-set
  kv_persist.h (121 lines) — .coli_kv disk persistence
  telemetry.h  (189 lines) — dashboard protocol, stats, usage

Main engine file shrinks from 6588 to 5396 lines (−18%).

Build system: primary target is now colibri$(EXE); `make glm`
remains as a phony alias for backward compat. CI, setup.sh,
coli CLI, and all 10 test files that include the engine are
updated. make check passes (C + Python, 73 tests, zero warnings).

c/tests/test_makefile_platform.py

@@ -35,7 +35,7 @@ class MakefilePlatformTests(unittest.TestCase):
         env["PATH"] = ""
 
         result = subprocess.run(
-            [MAKE, "--no-print-directory", "-B", "-n", "glm"],
+            [MAKE, "--no-print-directory", "-B", "-n", "colibri"],
             cwd=C_DIR,
             env=env,
             text=True,
@@ -43,7 +43,7 @@ class MakefilePlatformTests(unittest.TestCase):
             check=True,
         )
 
-        self.assertIn("-o glm.exe", result.stdout)
+        self.assertIn("-o colibri.exe", result.stdout)
         self.assertIn("-fopenmp", result.stdout)
         self.assertIn("-static", result.stdout)