docs: add a changelog and a release checklist that surfaces breaking changes

.github/CHANGELOG.md

@@ -0,0 +1,63 @@
+# Changelog
+
+Notable changes to the OpenDia MCP server and browser extension.
+
+Release notes on the [Releases page](https://github.com/aeonfun/opendia/releases)
+are written from this file, so land your entry in **Unreleased** with the change
+itself rather than reconstructing it at tag time.
+
+## Unreleased
+
+### ⚠️ Breaking
+
+- **`--tunnel` now requires a bearer token.** Publishing the MCP server through a
+  tunnel used to mean anyone who learned the URL could drive your browser. `/sse`
+  is now authenticated whenever the surface leaves this machine (`--tunnel`, or
+  `--http-host=` set to a non-loopback address). The server generates a token at
+  startup and prints it; pin a fixed one with `--token=<value>`.
+
+  Existing tunnel users **must** add the header — an online AI connector that
+  worked before will start returning `401` until it does:
+
+  ```
+  Authorization: Bearer <token>
+  ```
+
+  Purely local setups (`npx opendia`, Claude Desktop over stdio, the browser
+  extension) are unaffected and need no token. (#55)
+
+### Security
+
+- Bind the extension control channel to loopback and gate its handshake. The
+  WebSocket server listened on all interfaces, and because the connection handler
+  hands the extension slot to whoever connects last, any reachable peer could evict
+  the real extension, receive every automation command, and return fabricated
+  results to the model. (#53)
+- Bind the HTTP/SSE surface to loopback and refuse page origins. `POST /sse` passes
+  its body to the MCP request handler, so the same control was reachable from the
+  LAN and — via `Access-Control-Allow-Origin: *` — cross-origin from any website you
+  visited. Both listeners now bind `127.0.0.1`, every request carrying a page
+  `Origin` is rejected, and CORS is reflected only for allowed origins. (#55)
+- Override `adm-zip` to `^0.6.0`, clearing GHSA-xcpc-8h2w-3j85 (crafted ZIP triggers
+  a 4GB allocation). Dev-only and not reachable from `web-ext lint`; the override
+  exists because `firefox-profile` pins `~0.5.x` and cannot reach the patch. It is a
+  stopgap — removal is tracked in #58. (#56)
+- Bump `node-forge` to 1.4.0 and `brace-expansion` to 1.1.15. (#43)
+
+### Maintenance
+
+- Dependency bumps: `ws` (#52), `web-ext` (#48), `actions/checkout` 4 → 7 (#46),
+  `actions/setup-node` 4 → 7 (#47, #51).
+- Consolidate community docs under `.github/` and add SECURITY + CONTRIBUTING (#44),
+  move `LICENSE` back to the repo root so GitHub detects it (#45), update
+  attribution to aeonfun / Aeon Inc (#49), aeon-style README (#50).
+
+## v1.1.1 — 2026-07-03
+
+MCP reliability fixes and Express 5. See the
+[release notes](https://github.com/aeonfun/opendia/releases/tag/v1.1.1).
+
+## v1.1.0 — 2025-07-20
+
+Timeout fixes and expanded documentation. See the
+[release notes](https://github.com/aeonfun/opendia/releases/tag/v1.1.0).

.github/CONTRIBUTING.md

@@ -78,6 +78,22 @@ npx web-ext lint --source-dir=dist/firefox --self-hosted   # Firefox lint
 - Reproduce the CI steps above locally and confirm they pass.
 - If you changed permissions, the tunnel, or the message bridge, call it out
   explicitly in the description — those touch the trust boundary.
+- Add a line to **Unreleased** in [`CHANGELOG.md`](CHANGELOG.md) if the change is
+  user-visible. Anything that makes an existing setup stop working goes under
+  `⚠️ Breaking`, with the migration step spelled out.
+
+## Releasing
+
+`.github/workflows/publish.yml` publishes `opendia-mcp/` to npm on a `v*` tag, so
+the tag is the point of no return. Before pushing one:
+
+1. Read **Unreleased** in [`CHANGELOG.md`](CHANGELOG.md) top to bottom. A
+   `⚠️ Breaking` entry means the release is a **major** bump, and the migration
+   step belongs at the top of the GitHub release notes — that is what users
+   actually read when something of theirs stops working.
+2. Rename `Unreleased` to the version and date, and open a fresh empty one.
+3. Bump `version` in `opendia-mcp/package.json` to match.
+4. Tag and push; write the release notes from the section you just closed.
 
 ## Reporting bugs & requesting features