Remove MCP backend, entrypoint injection, and docs; add migration shim

Completes the removal begun in the previous commit.

Backend: deletes models/mcp_server.rs, storage/mcp_store.rs and
commands/mcp_commands.rs, the McpStore on AppState, the four IPC
handlers, Project::enabled_mcp_servers, build_mcp_servers_json(),
compute_mcp_fingerprint(), the MCP_SERVERS_JSON env injection, the
mcp-fingerprint label, and the whole MCP container lifecycle.
create_container() and container_needs_recreation() lose their
mcp_servers/network_name parameters.

Container: entrypoint.sh no longer merges MCP_SERVERS_JSON into
~/.claude.json. MCP_SERVERS_JSON stays in the reserved env blocklist.

Security: the Docker socket is no longer auto-mounted for stdio+Docker
MCP servers — it now mounts only when allow_docker_access is set.

Migration: old containers were created with
network_mode=triple-c-net-<projectId> and refuse to start once that
network is gone. docker/network.rs becomes docker/legacy_cleanup.rs with
label-driven, best-effort removal of leftover MCP containers and the
per-project network, called on both delete and recreate.
container_needs_recreation() now forces a rebuild for any container
carrying a non-empty triple-c.mcp-fingerprint label or attached to a
triple-c-net-* network, moving it onto the default bridge. Both can be
dropped a release later.

Docs: drops the MCP sections from README/HOW-TO-USE/TECHNICAL and adds a
short note pointing at Claude Code's native `claude mcp` / `/mcp` /
.mcp.json instead.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/src-tauri/src/storage/mcp_store.rs

@@ -1,106 +0,0 @@
-use std::fs;
-use std::path::PathBuf;
-use std::sync::Mutex;
-
-use crate::models::McpServer;
-
-pub struct McpStore {
-    servers: Mutex<Vec<McpServer>>,
-    file_path: PathBuf,
-}
-
-impl McpStore {
-    pub fn new() -> Result<Self, String> {
-        let data_dir = dirs::data_dir()
-            .ok_or_else(|| "Could not determine data directory. Set XDG_DATA_HOME on Linux.".to_string())?
-            .join("triple-c");
-
-        fs::create_dir_all(&data_dir).ok();
-
-        let file_path = data_dir.join("mcp_servers.json");
-
-        let servers = if file_path.exists() {
-            match fs::read_to_string(&file_path) {
-                Ok(data) => {
-                    match serde_json::from_str::<Vec<McpServer>>(&data) {
-                        Ok(parsed) => parsed,
-                        Err(e) => {
-                            log::error!("Failed to parse mcp_servers.json: {}. Starting with empty list.", e);
-                            let backup = file_path.with_extension("json.bak");
-                            if let Err(be) = fs::copy(&file_path, &backup) {
-                                log::error!("Failed to back up corrupted mcp_servers.json: {}", be);
-                            }
-                            Vec::new()
-                        }
-                    }
-                }
-                Err(e) => {
-                    log::error!("Failed to read mcp_servers.json: {}", e);
-                    Vec::new()
-                }
-            }
-        } else {
-            Vec::new()
-        };
-
-        Ok(Self {
-            servers: Mutex::new(servers),
-            file_path,
-        })
-    }
-
-    fn lock(&self) -> std::sync::MutexGuard<'_, Vec<McpServer>> {
-        self.servers.lock().unwrap_or_else(|e| e.into_inner())
-    }
-
-    fn save(&self, servers: &[McpServer]) -> Result<(), String> {
-        let data = serde_json::to_string_pretty(servers)
-            .map_err(|e| format!("Failed to serialize MCP servers: {}", e))?;
-
-        // Atomic write: write to temp file, then rename
-        let tmp_path = self.file_path.with_extension("json.tmp");
-        fs::write(&tmp_path, data)
-            .map_err(|e| format!("Failed to write temp MCP servers file: {}", e))?;
-        fs::rename(&tmp_path, &self.file_path)
-            .map_err(|e| format!("Failed to rename MCP servers file: {}", e))?;
-        Ok(())
-    }
-
-    pub fn list(&self) -> Vec<McpServer> {
-        self.lock().clone()
-    }
-
-    pub fn get(&self, id: &str) -> Option<McpServer> {
-        self.lock().iter().find(|s| s.id == id).cloned()
-    }
-
-    pub fn add(&self, server: McpServer) -> Result<McpServer, String> {
-        let mut servers = self.lock();
-        let cloned = server.clone();
-        servers.push(server);
-        self.save(&servers)?;
-        Ok(cloned)
-    }
-
-    pub fn update(&self, updated: McpServer) -> Result<McpServer, String> {
-        let mut servers = self.lock();
-        if let Some(s) = servers.iter_mut().find(|s| s.id == updated.id) {
-            *s = updated.clone();
-            self.save(&servers)?;
-            Ok(updated)
-        } else {
-            Err(format!("MCP server {} not found", updated.id))
-        }
-    }
-
-    pub fn remove(&self, id: &str) -> Result<(), String> {
-        let mut servers = self.lock();
-        let initial_len = servers.len();
-        servers.retain(|s| s.id != id);
-        if servers.len() == initial_len {
-            return Err(format!("MCP server {} not found", id));
-        }
-        self.save(&servers)?;
-        Ok(())
-    }
-}

app/src-tauri/src/storage/mod.rs

@@ -1,7 +1,6 @@
 pub mod projects_store;
 pub mod secure;
 pub mod settings_store;
-pub mod mcp_store;
 
 #[allow(unused_imports)]
 pub use projects_store::*;
@@ -9,5 +8,3 @@ pub use projects_store::*;
 pub use secure::*;
 #[allow(unused_imports)]
 pub use settings_store::*;
-#[allow(unused_imports)]
-pub use mcp_store::*;