feat: add About well to settings with build info and debug easter egg (#145)

## Summary

Add a new well at the bottom of the settings view displaying application info (license, author, version, build date, git commit hash linked to Gitea), and an easter egg that reveals a debug mode toggle after clicking the version number 10 times.

## Changes

- **`src/popup/index.html`**: Added About well with license, author, version, build date, and linked commit hash. Added hidden debug well with debug mode toggle.
- **`src/popup/views/settings.js`**: Populate About well from build-time constants. Implement version click counter (10 clicks reveals debug well). Wire up debug mode toggle to state and runtime logger.
- **`src/shared/buildInfo.js`** (new): Module exporting build-time constants (`BUILD_VERSION`, `BUILD_LICENSE`, `BUILD_AUTHOR`, `BUILD_COMMIT`, `BUILD_DATE`, `GITEA_COMMIT_URL`) injected by esbuild define.
- **`build.js`**: Read git commit hash (short + full) and version from package.json, pass as esbuild `define` constants. Also reads `GIT_COMMIT_SHORT`/`GIT_COMMIT_FULL` env vars for Docker builds.
- **`Dockerfile`**: Accept `GIT_COMMIT_SHORT` and `GIT_COMMIT_FULL` build args, set as env vars for the build step.
- **`Makefile`**: Pass git commit hashes as Docker build args.
- **`src/shared/state.js`**: Add `debugMode` boolean to state (persisted).
- **`src/shared/log.js`**: Add runtime debug flag that supplements the compile-time `DEBUG` constant. Debug mode toggle updates this flag immediately.

closes #144

Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Co-authored-by: clawbot <clawbot@sneak.cloud>
Co-authored-by: user <user@Mac.lan guest wan>
Co-authored-by: clawbot <clawbot@eeqj.de>
Co-authored-by: sneak <sneak@sneak.berlin>
Reviewed-on: #145
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

src/shared/state.js

@@ -29,6 +29,7 @@ const DEFAULT_STATE = {
     fraudContracts: [],
     tokenHolderCache: {},
     theme: "system",
+    debugMode: false,
 };
 
 const state = {
@@ -68,6 +69,7 @@ async function saveState() {
         fraudContracts: state.fraudContracts,
         tokenHolderCache: state.tokenHolderCache,
         theme: state.theme,
+        debugMode: state.debugMode,
         currentView: state.currentView,
         selectedWallet: state.selectedWallet,
         selectedAddress: state.selectedAddress,
@@ -128,6 +130,8 @@ async function loadState() {
         state.fraudContracts = saved.fraudContracts || [];
         state.tokenHolderCache = saved.tokenHolderCache || {};
         state.theme = saved.theme || "system";
+        state.debugMode =
+            saved.debugMode !== undefined ? saved.debugMode : false;
         state.currentView = saved.currentView || null;
         state.selectedWallet =
             saved.selectedWallet !== undefined ? saved.selectedWallet : null;