feat(gateway): send the quest and group messages the client expects

[Mathih13]

Several quest and group states had no message to the client. A refused quest accept left the window silent. The client never heard that a quest log was full, that a member was kicked, or that an objective was done.

This change sends the vmangos message for each state that already exists:

• A refused accept sends SMSG_QUESTGIVER_QUEST_INVALID (level, race, already on the quest, other requirements), SMSG_QUESTLOG_FULL, or SMSG_QUESTGIVER_QUEST_FAILED with the inventory-full reason when the source item does not fit. Each refusal, a giver Refusal (range, role) included, ends with SMSG_GOSSIP_COMPLETE, as vmangos closes the gossip on every refusal path.
• The Module now refuses an accept when the quest log has no free slot. A slot is any un-rewarded row, failed ones included, because the client log shows them. A new row, or a rewarded repeatable row, needs a free slot. A failed or open row already holds one.
• CMSG_QUESTGIVER_CANCEL closes the gossip with SMSG_GOSSIP_COMPLETE.
• A finished explore objective, and a new external-event credit, send SMSG_QUESTUPDATE_COMPLETE before the quest-log sync.
• A member kicked from a Group that survives hears SMSG_GROUP_UNINVITE before SMSG_GROUP_DESTROYED. A kick that disbands the Group sends only SMSG_GROUP_DESTROYED. vmangos sends an empty SMSG_GROUP_LIST after the uninvite instead.

The acceptance Refusal text now lives in lyracore_shared::quest, so the Module and the Gateway cannot drift. The text is unchanged.

Tests: byte tests for the three new quest packets, Fake dispatcher tests for each Refusal, relay tests, and durable tests for the log-full check (new, repeatable and failed quests) and the kick events. CI runs the durable tests.

Verification:

• cargo fmt --all -- --check, Gateway clippy with -D warnings, Gateway tests (2028), Module lib tests (1581), shared tests (312) and the wasm check pass. The durable tests quest_log_full and group_uninvite compile with --no-run. CI runs them.
• Comment review: I read all added and changed comments in the final diff against origin/main, new test files included. It passed. I removed narration and kept one-line contracts: three packet layouts with opcodes, the Live insert replay rule, the gossip-close ordering, and the UNINVITED event meaning. No removed comment held a pointer or tool annotation.

Claude Sonnet 5.5 in Claude Code.