Add Tiny Tool Town submission canvas (#2240)

* Add Tiny Tool Town submission canvas

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

* Add generated description choices

Resolve picker opens from the active session working directory so linked worktrees work without an explicit repository path.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

* Address Tiny Tool review comments

Detect root .csproj files as build signals and hide canvas access tokens from the visible URL after first load.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

* Address latest Tiny Tool review comments

Handle root-relative README images, preserve drafts during refresh, and suppress GitHub mentions before public issue creation.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

* Address canvas shutdown and CSP review

Close all canvas servers during shutdown, use nonce-based CSP, make theme optional, and hide decorative preview dots from assistive tech.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: jamesmontemagno

.github/plugin/marketplace.json

@@ -1062,6 +1062,12 @@
       "description": "Comprehensive collection for writing tests, test automation, and test-driven development including unit tests, integration tests, and end-to-end testing strategies.",
       "version": "1.0.0"
     },
+    {
+      "name": "tiny-tool-town-submitter",
+      "source": "extensions/tiny-tool-town-submitter",
+      "description": "Inspect a repository, improve Tiny Tool Town readiness, submit its listing issue, and launch remediation work.",
+      "version": "1.0.0"
+    },
     {
       "name": "token-pacman",
       "source": "extensions/token-pacman",

extensions/tiny-tool-town-submitter/.github/plugin/plugin.json

@@ -0,0 +1,19 @@
+{
+  "name": "tiny-tool-town-submitter",
+  "description": "Inspect a repository, improve Tiny Tool Town readiness, submit its listing issue, and launch remediation work.",
+  "version": "1.0.0",
+  "author": {
+    "name": "James Montemagno",
+    "url": "https://github.com/jamesmontemagno"
+  },
+  "keywords": [
+    "github-issues",
+    "open-source",
+    "project-readiness",
+    "repository-analysis",
+    "submission-workflow",
+    "tiny-tool-town"
+  ],
+  "logo": "assets/preview.png",
+  "extensions": "."
+}

extensions/tiny-tool-town-submitter/README.md

@@ -0,0 +1,18 @@
+# Tiny Tool Town Submitter
+
+Inspect the current Git repository, review every field required by Tiny Tool Town, and submit a complete listing issue from a Copilot canvas.
+
+The canvas also checks public-repository readiness, detects missing README guidance, licenses, and showcase imagery, and can request a dedicated Copilot project session to implement selected recommendations.
+
+## Actions
+
+- **Re-scan repository** refreshes detected metadata and readiness findings.
+- **Generate options** uses the Copilot SDK to draft short, balanced, and detailed listing descriptions that can be reviewed before applying.
+- **Start improvement session** hands selected findings to a new local project session.
+- **Submit to Tiny Tool Town** checks required confirmations, searches for an existing submission, and creates the public issue through GitHub CLI.
+
+GitHub CLI must be installed and authenticated to verify repository visibility or submit an issue.
+
+## Assets
+
+- `assets/preview.png` shows the submission workshop canvas.