Revert "research: delete Hono backend (do not merge) (#25667)" and cleanup

This reverts:
- 28b03595b research: delete Hono backend (do not merge) (#25667)
- b24a4e897 chore(server): clean up post-Hono-deletion scar tissue (#26542)

v1.14.42 broke startup for users with plugins that depend on the
Hono wire format (most visibly opencode-gemini-auth, see #26546).
Restoring Hono as the default backend on stable channels while we
investigate the actual plugin compatibility story.

OPENCODE_EXPERIMENTAL_HTTPAPI flag and dual-backend selection come
back. Stable installs default to Hono; dev/beta default to HTTP API.

Conflict resolution: took the pre-deletion side for control-plane
schemas and the seven test files where post-deletion follow-up PRs
had also touched the conflicting lines. The HTTP API code added
since the deletion (compression, cors-vary, fence, lifecycle log,
account error mapping, etc.) is preserved as-is — those still apply
on the HTTP API path for users on dev/beta channels.

bun.lock

@@ -393,6 +393,10 @@
         "@effect/opentelemetry": "catalog:",
         "@effect/platform-node": "catalog:",
         "@gitlab/opencode-gitlab-auth": "1.3.3",
+        "@hono/node-server": "1.19.11",
+        "@hono/node-ws": "1.3.0",
+        "@hono/standard-validator": "0.1.5",
+        "@hono/zod-validator": "catalog:",
         "@lydell/node-pty": "catalog:",
         "@modelcontextprotocol/sdk": "1.27.1",
         "@octokit/graphql": "9.0.2",
@@ -433,6 +437,8 @@
         "glob": "13.0.5",
         "google-auth-library": "10.5.0",
         "gray-matter": "4.0.3",
+        "hono": "catalog:",
+        "hono-openapi": "catalog:",
         "ignore": "7.0.5",
         "immer": "11.1.4",
         "jsonc-parser": "3.3.1",
@@ -459,6 +465,7 @@
         "xdg-basedir": "5.1.0",
         "yargs": "18.0.0",
         "zod": "catalog:",
+        "zod-to-json-schema": "3.24.5",
       },
       "devDependencies": {
         "@babel/core": "7.28.4",
@@ -491,6 +498,7 @@
         "typescript": "catalog:",
         "vscode-languageserver-types": "3.17.5",
         "why-is-node-running": "3.2.2",
+        "zod-to-json-schema": "3.24.5",
       },
     },
     "packages/plugin": {
@@ -1231,6 +1239,8 @@
 
     "@hono/node-server": ["@hono/node-server@1.19.11", "", { "peerDependencies": { "hono": "^4" } }, "sha512-dr8/3zEaB+p0D2n/IUrlPF1HZm586qgJNXK1a9fhg/PzdtkK7Ksd5l312tJX2yBuALqDYBlG20QEbayqPyxn+g=="],
 
+    "@hono/node-ws": ["@hono/node-ws@1.3.0", "", { "dependencies": { "ws": "^8.17.0" }, "peerDependencies": { "@hono/node-server": "^1.19.2", "hono": "^4.6.0" } }, "sha512-ju25YbbvLuXdqBCmLZLqnNYu1nbHIQjoyUqA8ApZOeL1k4skuiTcw5SW77/5SUYo2Xi2NVBJoVlfQurnKEp03Q=="],
+
     "@hono/standard-validator": ["@hono/standard-validator@0.1.5", "", { "peerDependencies": { "@standard-schema/spec": "1.0.0", "hono": ">=3.9.0" } }, "sha512-EIyZPPwkyLn6XKwFj5NBEWHXhXbgmnVh2ceIFo5GO7gKI9WmzTjPDKnppQB0KrqKeAkq3kpoW4SIbu5X1dgx3w=="],
 
     "@hono/zod-validator": ["@hono/zod-validator@0.4.2", "", { "peerDependencies": { "hono": ">=3.9.0", "zod": "^3.19.1" } }, "sha512-1rrlBg+EpDPhzOV4hT9pxr5+xDVmKuz6YJl+la7VCwK6ass5ldyKm5fD+umJdV2zhHD6jROoCCv8NbTwyfhT0g=="],