ci: bump observer channel base version to v1.17.0

Both channels move together: the beta workflow's FIRMWARE_VERSION must equal
production's, since a node compares its embedded base against its own channel's
manifest and a mismatch would read as permanently behind.

Resets the per-base build counter to N=1 on both channels. Nodes still on
v1.16.0.N take the diff_base branch in ESP32Board's OTA comparison ('different
base version is always an update'), so the counter going backwards does not
strand them; the build-number arithmetic only runs when the base matches.

The flasher repo's config.json version key still needs the matching bump.

.github/workflows/build-observer-firmwares-beta.yml

@@ -56,7 +56,7 @@ env:
   # OTA comparison treats a different base version as "always an update", so a
   # distinct base here would make every beta node think it is permanently behind.
   # Channels are separated by manifest URL, not by base version.
-  FIRMWARE_VERSION: v1.16.0
+  FIRMWARE_VERSION: v1.17.0
 
   # Beta-only rolling release. A separate tag is required, not cosmetic: the
   # publish step prunes all but the KEEP_BUILDS most recent build hashes within

.github/workflows/build-observer-firmwares.yml

@@ -41,7 +41,7 @@ concurrency:
 env:
   # Version embedded in firmware filenames; must match the version key in the
   # flasher's config.json. Bump here when the observer version changes.
-  FIRMWARE_VERSION: v1.16.0
+  FIRMWARE_VERSION: v1.17.0
   # Rolling release tag that hosts the latest observer binaries.
   RELEASE_TAG: observer-mqtt-latest
   # Download host serving RELEASE_TAG's assets (cloudflare-worker in the flasher