fix(scripts/releaser/v1): remove doubled "v" in release calendar latest release link (#27260)

## Problem

The interactive releaser (`scripts/releaser`) renders the "Latest
Release"
cell of the release calendar with a doubled version prefix, e.g.
`[vv2.35.0](.../tag/v2.35.0)`.

`version.String()` already returns a `v`-prefixed string (e.g.
`v2.35.0`),
but `updateCalendar` wrapped it in a `"[v%s]"` template, so the link
label
gained a second `v`. The tag URL was already correct because release
tags
carry the `v` prefix.

## Fix

Drop the extra `v` from the label template (`"[v%s]"` → `"[%s]"`). The
URL is
unchanged.

- Label before: `[vv2.35.0]`
- Label after: `[v2.35.0]`

## Test

Added `scripts/releaser/v1/docs_test.go`:

- `TestUpdateCalendarLatestReleaseVersionPrefix` asserts the
`LatestRelease`
cell for a matching row on both a patch and a minor release. It fails on
the
  old code (`[vv2.35.x]`) and passes with the fix.
- `TestUpdateCalendarNotReleasedRowName` covers the `Not Released` →
`Mainline`
  promotion and the major.minor "Release name" link (patch omitted).

<details>
<summary>Investigation notes</summary>

- Entry path: `scripts/release.sh` → `go run ./scripts/releaser
--legacy` →
  `runRelease` → `promptAndUpdateDocs` → `updateReleaseDocs` →
`updateCalendarFile` → `updateCalendar` (`scripts/releaser/v1/docs.go`).
- Root cause in `updateCalendar`: `fmt.Sprintf("[v%s](%s)",
newVer.String(), ...)`
  combined with `version.String()` returning `v%d.%d.%d`.
- Only the link label was affected; the `releaseTagURLFmt` URL was
correct
  because tags are `v`-prefixed.
- The standalone `scripts/update-release-calendar.sh` is a separate
implementation and is not affected (it strips the `v` before re-adding
one).
- Companion PR for `release/2.35` (file `scripts/releaser/docs.go`):
#27259.

</details>

---
This PR was generated by Coder Agents.

scripts/releaser/v1/docs.go

@@ -171,7 +171,7 @@ func updateCalendar(
 	for i, r := range rows {
 		if r.Major == newVer.Major && r.Minor == newVer.Minor {
 			rows[i].LatestRelease = fmt.Sprintf(
-				"[v%s](%s)",
+				"[%s](%s)",
 				newVer.String(),
 				fmt.Sprintf(releaseTagURLFmt, newVer.String()),
 			)

scripts/releaser/v1/docs_test.go

@@ -0,0 +1,85 @@
+package v1 //nolint:testpackage // Tests unexported release helpers.
+
+import "testing"
+
+// TestUpdateCalendarLatestReleaseVersionPrefix checks the formatting of the
+// "Latest Release" cell produced by updateCalendar. version.String() already
+// includes a leading "v", so the link label must not add a second one, while
+// the release tag URL keeps the "v" because tags are prefixed with it.
+func TestUpdateCalendarLatestReleaseVersionPrefix(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		newVer  version
+		channel string
+		want    string
+	}{
+		{
+			name:    "patch release",
+			newVer:  version{Major: 2, Minor: 35, Patch: 1},
+			channel: "mainline",
+			want:    "[v2.35.1](https://github.com/coder/coder/releases/tag/v2.35.1)",
+		},
+		{
+			name:    "minor release",
+			newVer:  version{Major: 2, Minor: 35, Patch: 0},
+			channel: "mainline",
+			want:    "[v2.35.0](https://github.com/coder/coder/releases/tag/v2.35.0)",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			rows := []calendarRow{{
+				ReleaseName:   "2.35",
+				Major:         2,
+				Minor:         35,
+				ReleaseDate:   "February 03, 2026",
+				Status:        "Mainline",
+				LatestRelease: "N/A",
+			}}
+
+			got := updateCalendar(rows, tt.newVer, tt.channel)
+
+			var cell string
+			for _, r := range got {
+				if r.Major == tt.newVer.Major && r.Minor == tt.newVer.Minor {
+					cell = r.LatestRelease
+					break
+				}
+			}
+
+			if cell != tt.want {
+				t.Fatalf("LatestRelease = %q, want %q", cell, tt.want)
+			}
+		})
+	}
+}
+
+// TestUpdateCalendarNotReleasedRowName checks that a "Not Released" row is
+// promoted to "Mainline" with a major.minor "Release name" link (patch
+// omitted) once its minor version is released.
+func TestUpdateCalendarNotReleasedRowName(t *testing.T) {
+	t.Parallel()
+
+	rows := []calendarRow{{
+		ReleaseName:   "2.36",
+		Major:         2,
+		Minor:         36,
+		Status:        "Not Released",
+		LatestRelease: "N/A",
+	}}
+
+	got := updateCalendar(rows, version{Major: 2, Minor: 36, Patch: 0}, "mainline")
+
+	if got[0].Status != "Mainline" {
+		t.Errorf("Status = %q, want %q", got[0].Status, "Mainline")
+	}
+	const want = "[2.36](https://coder.com/changelog/coder-2-36)"
+	if got[0].ReleaseName != want {
+		t.Fatalf("ReleaseName = %q, want %q", got[0].ReleaseName, want)
+	}
+}