fix(election-iomgr-refactor): Raft election, config decode, and RDHUP chain

- ha.c: self-vote in ha_start_election_async (Raft invariant)
- ha.c: heartbeat_timeout_ms for hb_timeout_thread (not election_timeout_ms)
- ha.c: clear voted_for before RDHUP jitter (stale vote from dead primary)
- ha.c: same-term voted_for check in RDHUP jitter
- config_repl.c/h: use xce_decode for upgradeConfig (capnp extraction before capn_free)
- cluster.c: fix upgradeConfig handler direction (standbys apply, primaries skip)
- cluster.c: remove raw_pkt_copy hack; use req directly
- join.c: push config to newly-joined standbys
- typemap.h/request.h/request.c: raw_sha256/raw_bytes fields for decoded upgradeConfig
- test_ha_failover.c: update heartbeat timeout test to use g_fast_cfg

src/include/typemap.h

@@ -348,8 +348,22 @@ struct repl_config_push_reply_s {
 };
 
 struct upgrade_config_req_s {
-    xce_data_t  *sha256;      /* 32-byte SHA-256 of proposed config */
-    xce_data_t  *bytes;       /* serialised ClusterConfig blob */
+    /* Legacy decoded fields — populated by generated decode_UpgradeConfigRequest()
+     * via decode_Data_ptr.  These are structurally broken for List(UInt8) wire
+     * fields (decode_Data_ptr reads a discriminant and misinterprets the bytes),
+     * but must remain for the generated code to compile.  Do NOT use these for
+     * actual byte extraction. */
+    xce_data_t  *sha256;      /* broken: always a bogus xce_jobs_data_t */
+    xce_data_t  *bytes;       /* broken: always a bogus xce_jobs_data_t */
+
+    /* Correct raw bytes extracted by xce_decode() before capn_free() runs,
+     * using UpgradeConfigRequest_get_sha256/bytes + capn_getv8.
+     * Both are malloc'd and owned here; freed by free_upgrade_config_req_raw()
+     * called from free_Request() after free_UpgradeConfigRequest().
+     * raw_sha256 is exactly 32 bytes when non-NULL. */
+    uint8_t *raw_sha256;      /* 32-byte SHA-256, malloc'd, or NULL */
+    uint8_t *raw_bytes;       /* serialised ClusterConfig blob, malloc'd, or NULL */
+    size_t   raw_bytes_len;   /* length of raw_bytes */
 };
 
 struct upgrade_config_reply_s {