chore(deps): migrate from eventide to kotatsu (#428)

## Summary

- The `eventide` dep was renamed to
[kotatsu](https://github.com/clice-io/kotatsu) with a broad rename of
CMake identifiers, namespaces, header paths, and a few module reorgs
(`serde` → `codec`, `reflection` → `meta`, `common` → `support`). Align
clice to the new names.
- CMake: FetchContent target, option prefix (`ETD_*` → `KOTA_*`,
`ETD_SERDE_*` → `KOTA_CODEC_*`), target names
(`eventide::{ipc::lsp,serde::toml,deco,zest}` →
`kota::{ipc::lsp,codec::toml,deco,zest}`).
- Namespaces: `eventide::` → `kota::`, `eventide::serde::` →
`kota::codec::`, `eventide::refl::` → `kota::meta::`. The short `et`
alias is dropped — all usages now spell `kota::` directly.
- Headers: `eventide/*` → `kota/*`, including special cases
`serde/serde/raw_value.h` → `codec/raw_value.h`, `ipc/json_codec.h` →
`ipc/codec/json.h`, `common/meta.h` → `support/type_traits.h`,
`common/ranges.h` → `support/ranges.h`.
- Kotatsu split `JsonPeer` / `BincodePeer` out of `ipc/peer.h` into the
codec-specific headers; added `kota/ipc/codec/{json,bincode}.h` includes
where those types are used.
- Depends on clice-io/kotatsu#110 (already merged) to prevent `-Wall
-Wextra -Werror` from transitively propagating out of
`kota::project_options`.

## Test plan

- [x] `pixi run unit-test RelWithDebInfo` — 518/518 pass (9 skipped,
unchanged from main)
- [x] `pixi run integration-test RelWithDebInfo` — 119/119 pass
- [x] `pixi run smoke-test RelWithDebInfo` — 2/2 pass
- [x] `pixi run format` clean

## Notes

- `tests/smoke/rapid_edit.jsonl` was intentionally left untouched: the
embedded `#include "eventide/..."` strings are frozen snapshots of file
contents the client sent at record time, not clice source.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Chores**
* Updated internal dependencies from `eventide` to `kota`, including
async runtime, IPC transport, serialization codec, and metadata
libraries.
* Updated build configuration and CMake variables to align with the new
dependency.

* **Refactor**
* Migrated internal implementation to use `kota` namespace and APIs
throughout the codebase.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/unit/server/stateful_worker_tests.cpp

@@ -2,16 +2,15 @@
 #include <vector>
 
 #include "test/test.h"
-#include "eventide/serde/serde/raw_value.h"
 #include "server/protocol.h"
 #include "server/worker_test_helpers.h"
 
+#include "kota/codec/raw_value.h"
+
 namespace clice::testing {
 
 namespace {
 
-namespace et = eventide;
-
 TEST_SUITE(StatefulWorker) {
 
 TEST_CASE(SpawnAndExit) {
@@ -33,7 +32,7 @@ TEST_CASE(CompileRequest) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::CompileParams params;
         params.path = src;
         params.version = 1;
@@ -59,7 +58,7 @@ TEST_CASE(HoverWithoutCompile) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         // Hover on a file that hasn't been compiled should return null.
         worker::QueryParams params;
         params.kind = worker::QueryKind::Hover;
@@ -88,7 +87,7 @@ TEST_CASE(CompileThenHover) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         // First compile
         worker::CompileParams cp;
         cp.path = src;
@@ -129,7 +128,7 @@ TEST_CASE(DocumentUpdate) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         // Compile first
         worker::CompileParams cp;
         cp.path = src;
@@ -170,7 +169,7 @@ TEST_CASE(CodeActionReturnsEmpty) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::QueryParams params;
         params.kind = worker::QueryKind::CodeAction;
         params.path = "/tmp/test.cpp";
@@ -192,7 +191,7 @@ TEST_CASE(GoToDefinitionReturnsEmpty) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::QueryParams params;
         params.kind = worker::QueryKind::GoToDefinition;
         params.path = "/tmp/test.cpp";
@@ -215,7 +214,7 @@ TEST_CASE(SemanticTokensWithoutCompile) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::QueryParams params;
         params.kind = worker::QueryKind::SemanticTokens;
         params.path = "/tmp/nonexistent.cpp";
@@ -236,7 +235,7 @@ TEST_CASE(FoldingRangeWithoutCompile) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::QueryParams params;
         params.kind = worker::QueryKind::FoldingRange;
         params.path = "/tmp/nonexistent.cpp";
@@ -257,7 +256,7 @@ TEST_CASE(DocumentSymbolWithoutCompile) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::QueryParams params;
         params.kind = worker::QueryKind::DocumentSymbol;
         params.path = "/tmp/nonexistent.cpp";
@@ -278,7 +277,7 @@ TEST_CASE(DocumentLinkWithoutCompile) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::QueryParams params;
         params.kind = worker::QueryKind::DocumentLink;
         params.path = "/tmp/nonexistent.cpp";
@@ -299,7 +298,7 @@ TEST_CASE(InlayHintsWithoutCompile) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         worker::QueryParams params;
         params.kind = worker::QueryKind::InlayHints;
         params.path = "/tmp/nonexistent.cpp";
@@ -330,7 +329,7 @@ TEST_CASE(MultipleSequentialRequests) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         // Compile first so feature requests return real data.
         worker::CompileParams cp;
         cp.path = src;
@@ -402,7 +401,7 @@ TEST_CASE(MultipleDocuments) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         // Compile 3 different documents.
         for(int i = 0; i < 3; i++) {
             worker::CompileParams cp;
@@ -440,7 +439,7 @@ TEST_CASE(EvictNotification) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         // Send an evict notification — worker should remove the document without crashing.
         worker::EvictParams ep;
         ep.path = "/tmp/evict_test.cpp";
@@ -474,7 +473,7 @@ TEST_CASE(SpawnWithMemoryLimit) {
 
     bool test_done = false;
 
-    w.run([&]() -> et::task<> {
+    w.run([&]() -> kota::task<> {
         // Compile first.
         worker::CompileParams cp;
         cp.path = src;