refactor: simplify createPR and improve type hierarchy

- Replace 3 nearly-identical createPR branches (70+ lines each)
  with a single function using PLATFORM_CLI lookup table
- Add BaseContext interface and have PRContext/ProjectContext
  extend it to eliminate field duplication

Co-Authored-By: Claude <noreply@anthropic.com>

src/pr.ts

@@ -124,6 +124,36 @@ export async function getRemoteHostname(): Promise<string | null> {
   }
 }
 
+const PLATFORM_CLI: Record<Platform, {
+  bin: string;
+  args: (title: string, body: string, base: string, draft: boolean) => string[];
+  label: string;
+}> = {
+  github: {
+    bin: "gh",
+    args: (title, body, base, draft) => {
+      const a = ["pr", "create", "--title", title, "--body", body, "--base", base];
+      if (draft) a.push("--draft");
+      return a;
+    },
+    label: "gh pr create",
+  },
+  gitlab: {
+    bin: "glab",
+    args: (title, body, base, draft) => {
+      const a = ["mr", "create", "--title", title, "--description", body, "--target-branch", base];
+      if (draft) a.push("--draft");
+      return a;
+    },
+    label: "glab mr create",
+  },
+  gitea: {
+    bin: "tea",
+    args: (title, body, base, _draft) => ["pulls", "create", "--title", title, "--description", body, "--base", base],
+    label: "tea pulls create",
+  },
+};
+
 export async function createPR(
   platform: Platform,
   title: string,
@@ -131,80 +161,8 @@ export async function createPR(
   base: string,
   draft: boolean,
 ): Promise<string> {
-  if (platform === "github") {
-    const args = [
-      "pr",
-      "create",
-      "--title",
-      title,
-      "--body",
-      body,
-      "--base",
-      base,
-    ];
-    if (draft) args.push("--draft");
-
-    const proc = Bun.spawn(["gh", ...args], {
-      stdout: "pipe",
-      stderr: "pipe",
-    });
-    const exitCode = await proc.exited;
-    const stdout = await new Response(proc.stdout).text();
-    const stderr = await new Response(proc.stderr).text();
-
-    if (exitCode !== 0) {
-      throw new Error(
-        stderr.trim() || `gh pr create failed (exit code ${exitCode})`,
-      );
-    }
-
-    const match = stdout.match(/(https?:\/\/[^\s]+)/);
-    return match?.[1] ?? stdout.trim();
-  }
-
-  if (platform === "gitlab") {
-    const args = [
-      "mr",
-      "create",
-      "--title",
-      title,
-      "--description",
-      body,
-      "--target-branch",
-      base,
-    ];
-    if (draft) args.push("--draft");
-
-    const proc = Bun.spawn(["glab", ...args], {
-      stdout: "pipe",
-      stderr: "pipe",
-    });
-    const exitCode = await proc.exited;
-    const stdout = await new Response(proc.stdout).text();
-    const stderr = await new Response(proc.stderr).text();
-
-    if (exitCode !== 0) {
-      throw new Error(
-        stderr.trim() || `glab mr create failed (exit code ${exitCode})`,
-      );
-    }
-
-    const match = stdout.match(/(https?:\/\/[^\s]+)/);
-    return match?.[1] ?? stdout.trim();
-  }
-
-  const args = [
-    "pulls",
-    "create",
-    "--title",
-    title,
-    "--description",
-    body,
-    "--base",
-    base,
-  ];
-
-  const proc = Bun.spawn(["tea", ...args], {
+  const cli = PLATFORM_CLI[platform];
+  const proc = Bun.spawn([cli.bin, ...cli.args(title, body, base, draft)], {
     stdout: "pipe",
     stderr: "pipe",
   });
@@ -213,9 +171,7 @@ export async function createPR(
   const stderr = await new Response(proc.stderr).text();
 
   if (exitCode !== 0) {
-    throw new Error(
-      stderr.trim() || `tea pulls create failed (exit code ${exitCode})`,
-    );
+    throw new Error(stderr.trim() || `${cli.label} failed (exit code ${exitCode})`);
   }
 
   const match = stdout.match(/(https?:\/\/[^\s]+)/);

src/types.ts

@@ -12,22 +12,21 @@ export interface FileEntry {
   label: string;
 }
 
-export interface ProjectContext {
+export interface BaseContext {
   readme: string | null;
   packageDescription: string | null;
   structure: string | null;
-  recentCommits: string[];
   diff: string;
 }
 
-export interface PRContext {
-  readme: string | null;
-  packageDescription: string | null;
-  structure: string | null;
+export interface ProjectContext extends BaseContext {
+  recentCommits: string[];
+}
+
+export interface PRContext extends BaseContext {
   branchName: string;
   baseBranch: string;
   branchCommits: string[];
-  diff: string;
 }
 
 export interface CommitResult {