fix: use path-based versioning (/v2/open) not query param (?v=2)

docs/api-versioning.md

@@ -4,9 +4,9 @@
 
 The primary "API surface" of this site is the `/open` URL scheme bridge. External consumers (GitHub Action comments, CI scripts, integrations) construct `/open?...` URLs. Breaking changes to accepted parameters must not invalidate old links.
 
-## Current version: v1 (unversioned)
+## Current version: v1
 
-All existing `/open` URLs are treated as **v1**. The `v` query parameter is optional and defaults to `1`.
+The current URL scheme lives at `/open`. It is treated as v1.
 
 ### v1 parameter sets
 
@@ -27,21 +27,23 @@ All existing `/open` URLs are treated as **v1**. The `v` query parameter is opti
 
 ## Versioning convention
 
-| Version | Path             | Status  |
-| ------- | ---------------- | ------- |
-| v1      | `/open`          | Current |
-| v2+     | `/open?v=2&...`  | Future  |
+New versions live at a new path prefix — not as a query parameter.
+
+| Version | Path        | Status  |
+| ------- | ----------- | ------- |
+| v1      | `/open`     | Current |
+| v2+     | `/v2/open`  | Future  |
 
 ### Rules
 
 1. **Never remove or rename params from an existing version.** Old links must keep working.
-2. **Introduce a new version for breaking changes.** Add `v=2` (or higher) when dropping, renaming, or reinterpreting existing params.
+2. **Introduce a new path for breaking changes.** Use `/v2/open` (or `/v3/open`, etc.) when dropping, renaming, or reinterpreting existing params.
 3. **New optional params are non-breaking.** They may be added to an existing version without a version bump.
-4. **The `v` param must be a positive integer string.** Unknown values return an error state with a clear message.
+4. **Old version routes stay alive indefinitely.** Do not delete `/open` when `/v2/open` ships.
 
 ## Adding a new version
 
-1. Extend the `resolveParams` function in `src/app/open/page.tsx` with a branch for the new version.
+1. Create `src/app/v2/open/` with its own `page.tsx` that implements the new param set.
 2. Add the new param set to this document under a new `## v<N> parameter sets` section.
-3. Keep the old version branch intact — do not delete it.
-4. Update the version table above.
+3. Update the version table above.
+4. Keep the old route untouched — do not modify it.

src/app/open/page.tsx

@@ -3,18 +3,16 @@
 import { useEffect, useRef, useState } from "react";
 import { type IssueParams, buildWorktreeUrl } from "./issue-card";
 import { NoParamsView } from "./no-params-view";
-import { UnknownVersionView } from "./unknown-version-view";
 import { OpeningView } from "./opening-view";
 import { InstallView } from "./install-view";
 import { OpenNav, OpenFooter } from "./open-layout";
 
 type Phase =
-  | "loading"         // reading URL params
-  | "opening"         // scheme triggered, awaiting user confirmation
-  | "success"         // user confirmed it opened
-  | "install"         // user says it didn't open → show install guide
-  | "no-params"       // no valid params in URL
-  | "unknown-version"; // unrecognized v= param
+  | "loading"    // reading URL params
+  | "opening"    // scheme triggered, awaiting user confirmation
+  | "success"    // user confirmed it opened
+  | "install"    // user says it didn't open → show install guide
+  | "no-params"; // no valid params in URL
 
 function get(sp: URLSearchParams, key: string): string {
   const val = sp.get(key);
@@ -44,23 +42,13 @@ function resolveParams(sp: URLSearchParams): IssueParams | null {
   return { kind: "github", owner, repo, issue };
 }
 
-const SUPPORTED_VERSIONS: string[] = ["1"];
-
 export default function OpenPage() {
   const [phase, setPhase] = useState<Phase>("loading");
   const [params, setParams] = useState<IssueParams | null>(null);
-  const [urlVersion, setUrlVersion] = useState<string>("1");
   const schemeTriggered = useRef(false);
 
   useEffect(() => {
     const sp = new URLSearchParams(window.location.search);
-    const raw = sp.get("v");
-    const v = raw !== null ? raw : "1";
-    setUrlVersion(v);
-    if (!SUPPORTED_VERSIONS.includes(v)) {
-      setPhase("unknown-version");
-      return;
-    }
     const p = resolveParams(sp);
     if (!p) { setPhase("no-params"); return; }
     setParams(p);
@@ -83,7 +71,6 @@ export default function OpenPage() {
       <main className="open-main">
         <div className="open-content">
           {phase === "no-params" && <NoParamsView />}
-        {phase === "unknown-version" && <UnknownVersionView version={urlVersion} />}
           {phase === "loading" && (
             <div className="loading-center">
               <div className="spinner-lg anim-spin" />