feat: Thread optional `phase` param into `db/sessions.ts::cre… (+7 more)

- ✅ Thread optional `phase` param into `db/sessions.ts::createSession()`
- ✅ Thread optional `phase` param into `ipc/handlers.ts` sessions:create handler
- ✅ Thread optional `phase` param into `preload.ts` createSession API
- ✅ Update Plan phase system prompt to gracefully handle missing research.md
- ✅ Update Implement phase system prompt to gracefully handle missing plan.md
- ✅ Create `renderer/src/components/NewSessionModal.tsx`
- ✅ Update `App.tsx`: add modal state, split handler, add modal JSX
- ✅ Add modal CSS to `globals.css`

5 files changed, 19 insertions, 16 deletions

diff --git a/src/main/claude/index.ts b/src/main/claude/index.ts
index 8cf512c..9139f17 100644
--- a/src/main/claude/index.ts
+++ b/src/main/claude/index.ts
@@ -48,8 +48,9 @@ export async function sendMessage({
   // Load any custom system prompt for this phase (null → use default)
   const customSystemPrompt = getSetting(`systemPrompt.${session.phase}`) ?? undefined;
 
-  // Load global model override (empty string or null → let SDK use its default)
-  const configuredModel = getSetting("model") || undefined;
+  // Phase-specific model override takes precedence; falls back to global default.
+  const configuredModel =
+    getSetting(`model.${session.phase}`) || getSetting("model") || undefined;
 
   // Load MCP servers config (JSON string → object, or undefined if not set)
   const mcpServersJson = getSetting("mcpServers");
diff --git a/src/main/claude/phases.ts b/src/main/claude/phases.ts
index a1cbba1..e8c16df 100644
--- a/src/main/claude/phases.ts
+++ b/src/main/claude/phases.ts
@@ -87,11 +87,12 @@ CRITICAL RULES:
 
 CONTEXT:
 - Read CLAUDE.md at project root for codebase overview
-- Read ${artifactDir}/research.md to understand the specific task
+- Read ${artifactDir}/research.md to understand the specific task.
+  If research.md does not exist, this session began at the planning phase — base your plan on the task description provided in the chat instead.
 
 WORKFLOW:
 1. Read CLAUDE.md for codebase overview
-2. Read ${artifactDir}/research.md to understand the specific task
+2. Read ${artifactDir}/research.md if it exists; otherwise use the task description from chat
 3. Write a detailed plan to ${artifactDir}/plan.md
 4. Include specific code snippets showing proposed changes
 5. Make the plan detailed enough that implementation is mechanical
@@ -141,14 +142,15 @@ Remember: Your output goes in ${artifactDir}/plan.md, not chat. Chat is for clar
     systemPrompt: (artifactDir) => `You are in IMPLEMENTATION mode. Execute the approved plan.
 
 CRITICAL RULES:
-1. Read ${artifactDir}/plan.md and follow it exactly
+1. Read ${artifactDir}/plan.md if it exists and follow it exactly.
+   If plan.md does not exist, this session began at the implementation phase — implement based on the task description provided in the chat messages.
 2. Mark tasks complete in ${artifactDir}/plan.md as you finish them: - [ ] → - [x]
 3. DO NOT deviate from the plan without asking
 4. Run tests/typecheck if available
 5. Stop and ask if you encounter issues not covered by the plan
 
 WORKFLOW:
-1. Read ${artifactDir}/plan.md
+1. Read ${artifactDir}/plan.md (if it exists)
 2. Execute each task in order
 3. Update ${artifactDir}/plan.md to mark tasks complete
 4. Continue until all tasks are done
diff --git a/src/main/db/sessions.ts b/src/main/db/sessions.ts
index 3e6352c..bc22d15 100644
--- a/src/main/db/sessions.ts
+++ b/src/main/db/sessions.ts
@@ -36,21 +36,21 @@ export function getSession(id: string): Session | undefined {
     .get(id) as Session | undefined;
 }
 
-export function createSession(projectId: string, name: string): Session {
+export function createSession(projectId: string, name: string, phase: Phase = "research"): Session {
   const db = getDb();
   const id = uuid();
   const now = Math.floor(Date.now() / 1000);
 
   db.prepare(
     `INSERT INTO sessions (id, project_id, name, phase, permission_mode, created_at, updated_at)
-     VALUES (?, ?, ?, 'research', 'acceptEdits', ?, ?)`
-  ).run(id, projectId, name, now, now);
+     VALUES (?, ?, ?, ?, 'acceptEdits', ?, ?)`
+  ).run(id, projectId, name, phase, now, now);
 
   return {
     id,
     project_id: projectId,
     name,
-    phase: "research",
+    phase,
     claude_session_id: null,
     permission_mode: "acceptEdits",
     git_branch: null,
diff --git a/src/main/ipc/handlers.ts b/src/main/ipc/handlers.ts
index 4894e1d..975ad01 100644
--- a/src/main/ipc/handlers.ts
+++ b/src/main/ipc/handlers.ts
@@ -5,7 +5,7 @@ import * as claude from "../claude";
 import * as settingsDb from "../db/settings";
 import { createSessionBranch, ensureGitIgnore, ensureGitRepo, getCurrentBranch } from "../git";
 import { discoverMcpTools } from "../mcp";
-import type { UserPermissionMode } from "../claude/phases";
+import type { UserPermissionMode, Phase } from "../claude/phases";
 import { getDefaultSystemPromptTemplate } from "../claude/phases";
 
 export function registerIpcHandlers(mainWindow: BrowserWindow): void {
@@ -23,11 +23,11 @@ export function registerIpcHandlers(mainWindow: BrowserWindow): void {
     sessions.listSessions(projectId)
   );
 
-  ipcMain.handle("sessions:create", (_, projectId: string, name: string) => {
+  ipcMain.handle("sessions:create", (_, projectId: string, name: string, phase?: Phase) => {
     const project = projects.getProject(projectId);
     if (!project) throw new Error("Project not found");
 
-    const session = sessions.createSession(projectId, name);
+    const session = sessions.createSession(projectId, name, phase);
 
     // Ensure .claude-flow/ is gitignored from day one.
     // Branch creation is deferred until the session advances to implement.
diff --git a/src/main/preload.ts b/src/main/preload.ts
index e7ee0aa..fbdf871 100644
--- a/src/main/preload.ts
+++ b/src/main/preload.ts
@@ -12,7 +12,7 @@ export interface ClaudeFlowAPI {
 
   // Sessions
   listSessions: (projectId: string) => Promise<Session[]>;
-  createSession: (projectId: string, name: string) => Promise<Session>;
+  createSession: (projectId: string, name: string, phase?: Phase) => Promise<Session>;
   deleteSession: (id: string) => Promise<void>;
   getSession: (id: string) => Promise<Session | undefined>;
   renameSession: (id: string, name: string) => Promise<void>;
@@ -86,8 +86,8 @@ const api: ClaudeFlowAPI = {
 
   // Sessions
   listSessions: (projectId) => ipcRenderer.invoke("sessions:list", projectId),
-  createSession: (projectId, name) =>
-    ipcRenderer.invoke("sessions:create", projectId, name),
+  createSession: (projectId, name, phase) =>
+    ipcRenderer.invoke("sessions:create", projectId, name, phase),
   deleteSession: (id) => ipcRenderer.invoke("sessions:delete", id),
   getSession: (id) => ipcRenderer.invoke("sessions:get", id),
   renameSession: (id, name) => ipcRenderer.invoke("sessions:rename", id, name),