[benchmark] Add light call and publish benchmarks (#15176)

tests/benchmarks/components/light/__init__.py

@@ -0,0 +1,28 @@
+import esphome.codegen as cg
+from esphome.components.light import generate_gamma_table
+from tests.testing_helpers import ComponentManifestOverride
+
+
+def override_manifest(manifest: ComponentManifestOverride) -> None:
+    # Light benchmarks need USE_LIGHT_GAMMA_LUT defined and a gamma table
+    # with external linkage that the benchmark .cpp can reference.
+    manifest.enable_codegen()
+    original_to_code = manifest.to_code
+
+    async def to_code(config):
+        await original_to_code(config)
+        cg.add_define("USE_LIGHT_GAMMA_LUT")
+        # Use the light component's own generate_gamma_table() so the
+        # benchmark stays in sync with any formula changes.
+        forward = generate_gamma_table(2.8)
+        values = ", ".join(f"0x{int(v):04X}" for v in forward)
+        # Use extern-visible (non-static) array so the benchmark .cpp
+        # can reference it via extern declaration.
+        cg.add_global(
+            cg.RawStatement(
+                f"extern const uint16_t bench_gamma_2_8_fwd[256] PROGMEM = {{{values}}};"
+            )
+        )
+
+    to_code.priority = original_to_code.priority
+    manifest.to_code = to_code