Add LSP completion/code actions/rename/signature help infrastructure, fix TypeScript LSP, rebrand app identifiers

- LSP Layer: Add completion, completion_resolve, signature_help, code_action,
  prepare_rename, and rename methods to TextDocumentService and LspServerModel
- Types: Add CompletionItemData, CompletionResult, SignatureHelpResult,
  CodeActionData, PrepareRenameResult, RenameResult, FileEdits
- Feature Flags: Add LspCompletion, LspCodeActions, LspRename, LspSignatureHelp
- Client Capabilities: Declare completion, signature help, rename, and code
  action capabilities so servers advertise these features
- Completion UI: Add completion state machine with debounced triggers, fuzzy
  filtering, positioned overlay menu, and edit application
- TypeScript LSP: Switch to npx for running typescript-language-server (handles
  download/caching automatically, survives node version switches)
- PATH Resolution: Add interactive shell PATH fallback for LSP server discovery
  and spawning (fixes nvm/fnm/volta users)
- App Identity: Rebrand from com.samsung.Galaxy/dev.warp.WarpOss to
  samsung.galaxy.GalaxyOss across bundle IDs, URL schemes, and plists
- Add scripts/reset-galaxy.sh for clean slate testing
- Galaxy status messages and other in-progress work

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/galaxy_core/src/channel/state.rs

@@ -37,7 +37,7 @@ pub struct ChannelState {
 impl ChannelState {
     pub fn init() -> Self {
         let channel = Channel::Oss;
-        let app_id = AppId::new("dev", "warp", "WarpOss");
+        let app_id = AppId::new("samsung", "galaxy", "GalaxyOss");
         Self {
             channel,
             additional_features: Default::default(),
@@ -379,13 +379,13 @@ impl ChannelState {
 
     pub fn url_scheme() -> &'static str {
         match Self::channel() {
-            Channel::Stable => "warp",
-            Channel::Preview => "warppreview",
-            Channel::Dev => "warpdev",
+            Channel::Stable => "galaxy",
+            Channel::Preview => "galaxypreview",
+            Channel::Dev => "galaxydev",
             // Dummy value--integration tests shouldn't support URL schemes.
-            Channel::Integration => "warpintegration",
-            Channel::Local => "warplocal",
-            Channel::Oss => "warposs",
+            Channel::Integration => "galaxyintegration",
+            Channel::Local => "galaxylocal",
+            Channel::Oss => "galaxyoss",
         }
     }
 }