[web_server] Self contained AP mode: embedded interface served as a captive portal (#18517)

tests/components/web_server/common-ap-fallback.yaml

@@ -0,0 +1,18 @@
+# STA with AP fallback plus local: true opts the fallback into captive AP mode; exercises
+# the runtime start (fallback branch in wifi loop) and end (on STA connect, and when the
+# provisioning window closes) paths.
+provisioning:
+  timeout: 1min
+
+api:
+  encryption:
+
+wifi:
+  ssid: MySSID
+  password: password1
+  ap:
+    ssid: "ESPHome-Test"
+    password: "Test1234!"
+
+web_server:
+  local: true

tests/components/web_server/common-ap-mode.yaml

@@ -0,0 +1,9 @@
+# AP mode: with a WiFi access point and the interface embedded in the firmware, web_server
+# runs its own captive portal (DNS server, unknown URLs redirect to the page).
+wifi:
+  ap:
+    ssid: "ESPHome-Test"
+    password: "Test1234!"
+
+web_server:
+  local: true

tests/components/web_server/test-ap-fallback.esp32-idf.yaml

@@ -0,0 +1,2 @@
+packages:
+  web_server: !include common-ap-fallback.yaml

tests/components/web_server/test-ap-mode.esp32-idf.yaml

@@ -0,0 +1,2 @@
+packages:
+  web_server: !include common-ap-mode.yaml

tests/components/web_server/test-ap-mode.esp8266-ard.yaml

@@ -0,0 +1,2 @@
+packages:
+  web_server: !include common-ap-mode.yaml