fix(seasons): derive the FUT web-file base from openfut.cfg, not a lab IP

`STAGING_FUT_BASE` hardcoded `http://10.10.0.120:8110/fut/` into the hook
binary, so the base-supply rewriter only worked on one machine and could not be
merged.

The prefix now comes from the same `openfut.cfg` / `openfut-common` source of
truth as every redirect target: `fut_content_base()` builds
`http://<host>:<fut_content_port>/fut/` from the configured host.
`OpenFutPorts` gains `fut_content` with a named default
(`default_ports::FUT_CONTENT = 8110`) and an optional `fut_content_port=` key,
matching how every other OpenFUT port is already handled. A cfg written before
the key existed still parses and takes the default — failing it would disarm the
network redirect too.

Arming fails SAFE: an absent or unusable config arms nothing and the rewriter
leaves every url exactly as the client built it, rather than pointing it at a
guessed host. This also adds the `openfut-common` dependency to the hook on this
branch; main already has it.

Proof: the cross-built artifact no longer contains the string 10.10.0.120
(previously compiled in), openfut-common is green at 16 tests including the new
config-derived-base and backward-compatibility cases, and the launcher builds.

openfut-hook/Cargo.toml

@@ -39,6 +39,10 @@ windows-sys = { version = "0.59", features = [
     "Win32_System_Diagnostics_Debug",
     "Win32_System_Kernel",
 ] }
+# Single source of truth for the OpenFUT redirect config (openfut.cfg schema,
+# EA-port -> OpenFUT-port map, WinSock byte-order helpers). Shared with the
+# launcher so the hook and openfut.cfg agree by construction.
+openfut-common = { path = "../openfut-common" }
 
 [profile.release]
 opt-level = "s"